Thanks to the Disney/Fox merger, Marvel Studios regained the rights to the X-Men and Fantastic Four. With that, 20th Century Fox's plans for both franchises were scrapped, with The New Mutants eventually released in theaters primarily due to contractual obligations.
While Marvel Studios wasted no time in announcing plans for a Fantastic Four reboot, the X-Men remain stuck in limbo. A cooling-off period is necessary in order to help moviegoers forget the likes of X-Men: Apocalypse and Dark Phoenix, though we will revisit that reality in next year's Deadpool 3 (a movie likely to end with Wade Wilson stranded in the MCU).
Despite that, Marvel Studios has started teasing the existence of mutants, with Ms. Marvel confirmed to have a genetic mutation and Namor referring to himself as a "mutant."
So, where are the X-Men?
"You know, I think we've said the word once," Kevin Feige laughed during an interview with Entertainment Weekly. "Kamala talks about a genetic mutation, and Namor refers to himself as a mutant amongst his own people. And mutant is a real genetic term, not just a comic book term."
"But part of the fun is that I've been at this company for half my life, and we're just now tapping into arguably one of the biggest aspects of the publishing history. It's pretty remarkable, and it's a testament to the house of ideas and what Marvel publishing has done these 80 years."
"The question is how to do it and when to do it, and that's something we've been working on for years. Now we know," he confirms. "But we're not going to talk about it. [Laughs]"
So, plans are in place for the X-Men to make their MCU debuts, but it's going to be a while before we're made privy to Marvel Studios' plans. It seems doubtful we'll meet the team in the Multiverse Saga, and the most popular theory right now is that Phases 7, 8, and 9 will make up the Mutant Saga.