Longtime X-Men producer Simon Kinberg has revealed how he thinks the team of mutant heroes should join the Marvel Cinematic Universe.

Despite his directorial debut on X-MenDark Phoenix being the biggest box office bomb of 2019, Kinberg has 14 years of X-Men experience that goes all the way back to X-Men: The Last Stand. After serving as writer and producer on X-Men: Apocalypse, Kinberg was promoted for Dark Phoenix -- which is rumored to be the end of the cinematic X-Men franchise fans have come to know since 2000. Now, he's given his own views on what should happen next.

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Discussing mutants in the MCU during a quarantine rewatch party of X-Men: Days of Future Past, Kinberg told IGN how Marvel Studios should explore the sci-fi aspects of the X-Men. "One of the things the MCU does so well, and I have such a profound respect as a fellow filmmaker and then as just a fan, is that they're really loyal to the comics," said Kinberg.

"They also are very unafraid of a more supernatural or science fiction tonality to their movies," he expanded. "They don't feel like they need to ground them so much in a sort of physics-based reality. I think there's something very great and liberating and spectacular about that. I think the X-Men could be very cool if you brought in science fiction elements and even the beyond Earth elements of the X-Men. That's something as a fan I would love to see, because I don't know that we've ever fully done that in a fully committed way in the Fox X-Men canon."

Christopher Nolan's Dark Knight trilogy kicked off the trend of realistic superhero movies. Josh Trank's Fantastic Four tried the gritty approach with 2015's critically panned movie, but according to Kinberg, the MCU should explore the out-there aspects of the X-Men comics. The X-Men have a long and complicated history with the cosmos and are no strangers to sci-fi elements.

Although Dark Phoenix briefly visited space, it was a loose adaptation of Chris Claremont and John Byrne's "The Dark Phoenix Saga." Jessica Chastain played a shapeshifting alien, however, aspects like Lilandra and the Shi'ar were swapped out for a largely Earth-based arc. Elsewhere, Dark Phoenix's ending was changed because it was too similar to Captain Marvel.

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As for the Marvel Cinematic Universe, the largely grounded days of Phase 1 have give way to far-fetched science fiction and outer space adventures. Alongside threats like Thanos and the galactic search for the Infinity Stones, movies including Guardians of the Galaxy and Captain Marvel have explored the stars. There have been mentions of a fully cosmic branch of the MCU, and the franchise's Phase 4 plans include more intergalactic stories with The Eternals.

Marvel Studios President Kevin Feige has promised he has plans for the X-Men in the MCU, but for the time being, Kinberg and everyone else is left wondering how and when mutants will be introduced.