It was announced a few days ago by FX President John Landgraf announced that Legion a show about Charles Xavier's son doesn't take place within the X-MEN film continuity, which is an odd decision because Fox has said before the critcally panned FANT4STIC, that they wanted to create a continuity that rivals the Marvel Cinematic Universe, with both the X-MEN and Fantastic Four properties, so you would think they would copy the whole merging the X-MEN TV stuff with the Movie stuff especially with a character like Legion who is Professor Xavier's son, and considering the fact Agents of SHIELD, Agent Carter, and Daredevil have all been successful while sharing the same universe space the Marvel Cinematic Universe, so it wouldn't make sense for Fox who wants to be the Marvel Cinematic Universe so bad that they even tried to pass of that the Fantastic Four sorta share the same universe as the X-MEN, so I doubt they would want to pull a DC with their properties especially when you read the reasons why Legion doesn't take place in the X-MEN film universe.
It's not in the continuity of those films in the sense the current X-Men films take place in a universe in which everybody on planet Earth is aware of the existence of mutants," he said. "The series Legion takes place in a parallel universe, if you will, in which the US government is in the early days of being aware that something called mutants exist but the public is not. I wouldn't foresee characters moving back and forth because they really are parallel universes."
It's not in the same universe because mutants are already known in the XCU, which would make sense for the present XCU, but how about the past XCU remember mutants were not known until 1973, and considering Charles Xavier was 30 years old in 1962 and 41 in 1973 so if they wanted to they can make it so that he's meets Gabriel Haller at the age of 24 which could have David Haller born in 1956 then have Legion TV show happen during the time where Mutants weren't known in the XCU, however FX didn't do that and FX is owned by Fox btw just in case you didn't know that is not the case.
I have a theory as to why Fox allowed this TV Show and possibly Hellfire to not take place in the XCU, it's simple they want to reboot all their Marvel properties in same way Sony is rebooting Spider-Man and it actually makes sense financially to.
The X-MEN Franchise doesn't have an exact direction they are going with their franchise, apart from X-MEN Apocalypse, Hugh Jackman's Wolverine the franchises cash cow is leaving, Deadpool can't be the face of the X-MEN franchise especially since he is way to hardcore to do that, and the Spider-Man deal between Marvel and Sony created so much buzz for Sony's MCU Spider-Man movie that they make 100 percent of the money on not Marvel, well ok apart from the license fee to Marvel which even Fox has to pay with all their X-MEN movies MCU or Not.
Fox doesn't want to lose the Fantastic Four rights, look at the reception for the Fantastic Four and look at the popular opinion on it, it's not stop making Fantastic Four movies, no it's give the rights to Marvel, people are already fancasting what an MCU Fantastic Four movie will, be hell alot of people weren't interested in what Hellfire and Legion mean for the XCU, but rather what did Marvel get out of the deal, Fox knows their shareholders won't allow them to make another Fantastic Four movie as it would be more profitable for them to just get rid of the property whether Marvel puts cash on the table or not, but investors will be mad if Fox doesn't make a deal like the one Sony has made with Marvel, people have faith in Marvel Studios alot more than what they have with Fox if a MCU Fantastic Four movie was made, it could easily make 400-500 million dollars money which could go into Fox's pocket if they just give Marvel creative control to actually do a good job with the characters.
"Why would the X-MEN be apart of this they are a success for Fox?
Let me ask you this how much money do you think an Avengers X-MEN Crossover movie make?
Yeah your probably be thinking 1. something billion dollars right? who do you think gets that 1. something billion dollars yes Fox, because if Marvel and Fox are working out a similar deal to the one Sony has with Marvel, Sony owns, finances, and has "final say pfft yeah right" on what happens to the property, Fox could simply give that 300 million dollars to Marvel Studios they go and spend it on who, what and whatever as they produce the film for Fox pretty much, Fox distrubutes the film, and makes 1 billion dollars back apart from 600-700 million that would be made on regular X-MEN movies not in the MCU, without MCU characters, instead they could be making 800 million dollars with the X-MEN movies and even include popular MCU characters in them like Spider-Man(yes their are X-MEN and Spider-Man crossover stories to use)
"FOX HAS PLANS AFTER WOLVERINE 3!!!!!!!!!!!!!!!"
No they do not, New Mutants and X-Force don't even have dates, Deadpool 2 hasn't been confirmed and even if it was that doesn't mean it has to take place in the current X-MEN universe and can easily take place in a rebooted MCU X-MEN franchise and it be rated R, same with New Mutants, and X-Force, and I would say Deadpool 1's events could easily be retconned either into the MCU in full, or only semi-canon just to cover the origin story part, and if what I'm hearing about Deadpool is true about it not really dealing with the timeline itself and just being it's own thing, not really mentioning that it takes place in the year yadda yadda but rather it just takes place in an ambigous part in modern time retconing it into the MCU would be so easy even someone who has the writing chops to make Twilight can do it, also if they did have plans to continue competing with Marvel then why would Legion be outside the XCU.
Now why I think Legion could be in the MCU if you look at Landgraf's words he said that Legion takes place in a world where it's the early days and mutants are just being heard about by the US Government, but not known by the public, to which the MCU fits the bill remember Inhumans are seen as aliens, they know powered people exist but not people who are born with powers, and mutants aren't really that big of phenomanon even in the Marvel 616 universe about less than 200 which is less than the Vactian, so it could be played off that the X-MEN either were not formed in the MCU, or they are, but like Spider-Man they were pretty street level, and unknown like Daredevil or like The Defenders will currently be, very under the radar until Legion where they are outed and have to be in the public to quell the publics reaction to mutants and any mutant hatred that can be formed, because even if Legion is in it's own universe completely unrelated to the movie universes mutants have to be outed at some point in the series and considering Xavier will have to be present at some point within the series, and if Fox wants to make an Avengers X-MEN Crossover movie then it makes no sense to have it off in it's own universe limited in terms of story and could cause a lack of interest in the TV show.
Population: Less than 200 before the Avengers vs. X-Men.
In fact the X-MEN in the MCU can play like this
Xavier meets Gabriel Haller he leaves her when he joins SHIELD but she is impregnated with his son David Haller.
Xavier, and Erik Lensheer are two of the original SHIELD Agents of the 1940s to 1960s, but they leave for Genosha and wanted his mutant status and mutants in general to be kept a secret, in 2017-2020 Xavier flees Genosha, because Magneto has become drunk with power and wants to take earth by force for the Mutants, so Xavier is looking for Mutants to make the X-MEN, the events of Legion out mutants to the world and general populace, Magneto comes, the Avengers/X-MEN take him down, The events of Deadpool 1 happen in 2021, Deadpool 2 takes place in 2022, X-Force and New Mutants I would say through them in whenever, Hellfire takes place in the past showing why Mutants are hidden in the MCU there as simple easy way to use mutants in the MCU without a massive continuity strain, just simple and easy.
I should also go into why I want the X-MEN rebooted into the MCU, Bryan Singer recently has said no one in X-MEN Apocalypse is safe and is planning on playing with alternate timelines you know, sort of like The Flash which in my opinion will further convolute the already convoluted X-MEN story, and has written itself into a whole and imho it's going overboard, that and I would like to see the X-MEN you know being the X-MEN, you know having a story centered around the themes of persecution for being different, and then not being afraid to break away from that story and that theme, I also want the X-MEN to be less limited in terms of story elements, I think it's just way to easy, and little bit lame to justify the whole oh they are the only powered people and that is why they are hated but I think it's very interesting to see how people react to how people get their powers of different walks and different origins, and I think the X-MEN have a very specific role in the MCU that can't be filled by the Inhumans, the fear of being replaced, the fear of going extinct, no one in the MCU can do this, not even the Inhumans.
The Inhumans are Kree experiments, that require terrigen to unlock their powers, and they are not born from the baseline of the human genome, baseline I mean regular humans like you and me, an Inhuman will always give birth to an Inhuman however a human will not always give birth to a human, and that is why humans are afraid of mutants more as opposed to Inhumans(who are seen as aliens), or the Avengers it's not just from a powers perspective, it's simply from a genome, extinction perspective