Marvel Studios expects to regain the rights to the X-Men and Fantastic Four in early 2019. The cinematic rights to the X-Men and Fantastic Four have been separated from the majority of the Marvel universe for a couple decades. Marvel Comics sold the film rights to their mutant characters and "First Family" to 20th Century Fox. This allowed the studio to make 2000's X-Men, which arguably started the superhero boom, and the much less successful Fantastic Four franchise(s).
Multimedia giant Disney, though, has fully acquired Marvel and is in the process of purchasing assets from 21st Century Fox. The deal between Fox and Disney isn't fully completed yet, but it almost certainly will happen. This means that the Marvel Cinematic Universe can grow exponentially and plans could be put in motion very, very soon.
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Variety interviewed Marvel Studios head Kevin Feige on their podcast with iHeartRadio, Playback. According to Feige, his cinematic superhero playbox could include mutants and the Reed family very soon. When asked if Marvel Studios currently has the rights to the Fox's superheroes, Feige answered:
No but we've been told it's looking very, very good and could happen in the first six months of next year.
Feige's answer isn't confirmation that Marvel Studios will use X-Men and/or the Fantastic Four in their immediate future, but that they can start officially planning soon. If anyone would know about these characters ing Marvel it would be Feige. Since 2007, he's been the president of Marvel Studios. Feige's the mastermind behind Iron Man and all the many movies that followed. Feige has been previously non-committal about any of Fox's properties being assimilated into the MCU, even after the news of "eager" about the possibility of using the X-Men. Feige's new comments to Variety suggest even if formal plans don't exist, they can start making those plans once the deal is closed.
This doesn't mean that the X-Men or Fantastic Four will be the MCU anytime soon. Even if Feige's timeline is correct and Marvel Studios does get the go ahead to use the characters, there still should be a few years wait while roles are cast, scripts are written and production is added to the schedule. This isn't even to mention that 20th Century Fox is still churning out mutant movies between mega-popular Deadpool and the still yet-to-be-released keep Deadpool going but the merc with a mouth still might need to be reworked to fit into the framework of Marvel Studios - if he s the MCU at all.
If any 20th Century Fox Marvel characters the MCU in the near future, it'll most likely be the Fantastic Four. Marvel's First Family would naturally fit into the Marvel Cinematic Universe's family-friendly and Spider-Man: Far from Home.
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Source: Variety