Altered Nova said:
There is no way Disney could logically retcon the X-men into the Marvel Cinematic Universe this late into the game. Mutants would have been around for a long time before all these world threatening events started happening and they absolutely would have been mentioned and shown up by now. Plus they've already changed Quicksilver and Scarlet Witch into volunteer science experiments who were given their powers by the Mind Gem.
Fantastic Four, Dr. Doom and Deadpool could be worked in with a bit of tweaking though. I would love to finally see a live action Dr. Doom who isn't a complete loser.
With as many alt-universes and cosmic BS that goes on in Marvel?
DC has stuff like that, but Marvel practically runs on it these days.
We're at the point where that kind of stuff is possible now that they have Dr. Strange and some of the more off the wall franchises doing well, such as Guardians of the Galaxy, which has always been about weird cosmic stuff. Adam Warlock has been teased in Guardians 2, which only opens the door for stuff like that even more.
Hell, the Spider-verse movie coming out next year gets directly into it. I know it's Sony, but it does establish this sort of thing for Marvel in the movies.
They could make an X-men movie that revolves around an 'event' that merges the two worlds without disrupting the current MCU plan or doing a complete reboot of the X-men stuff.
It will be fun to hear Deadpool comment on it when he gets a movie after all this is done.
It could be an aftereffect of any number of things that occur in the MCU as well. Some form of energy from the infinity stones, something Thanos does that causes lingering radiation, the Chitauri invasion having some form of after effect that took a while to manifest, something that happens in Captain Marvel involving the Kree that activates dormant genes that were only active in a few prior to whatever unlocks them. [Allowing for Wolverine, Professor X, Magneto, and a handful of other mutants to be older.]
Any number of Marvel villains could also kickstart some sort of mutant surge. Apocalypse, Mr. Sinister, High Evolutionary, etc...
It's a comic book movie, they can manage it pretty easily.
Also, the state of things in the MCU kind of makes things ripe for mutant hatred with how controversial super heroes and the damage they cause already are.
Infinity War isn't likely to help with that any if the trailers are any indication.
The X-men won't be that hard to work into things.
I also really want a Fantastic Four movie that doesn't suck and a legit Dr. Doom. He'd make a great big bad for the phase after they've finished with Thanos. A FF movie would be a great way to introduce him.