Director Tim Miller's had an interesting relationship with the X-Men universe onscreen. His feature film debut was 2016's Deadpool, a box office smash that ultimately brought in a whopping $783.1 million on a $58 million budget. When it came time to work on the sequel to Deadpool, Miller and star Ryan Reynolds (who has a lot of creative control over this franchise) didn't see eye to eye, with Miller choosing to leave the film altogether (something Reynolds insists made him sad). Since then, Miller's been connected to the Sonic the Hedgehog flick as well as the sixth (and final) Terminator movie, but new reports say Miller could be back in the X-Men world, developing a film for another mutant altogether.
Collider reports that Miller was developing a Kitty Pryde movie with Fox. For those who are unfamiliar, Kitty Pryde (who also has gone by the code name Shadowcat) has what's called a "phasing" ability, which basically means she can make herself (or people/objects she comes into contact with) intangible, allowing her to walk through walls and the like. She was the youngest X-Men ever recruited, had a history as Wolverine's sidekick, and in the comics, she's even been recruited by the Guardians of the Galaxy, being romantically linked with the Star-Lord.
You've also seen her onscreen before, most famously portrayed by Ellen Page in 2006's X-Men: The Last Stand and 2014's X-Men: Days of Future Past. Collider's report does not mention Page at all, however. This would be a solo film, with Miller possibly directing. Many wonder what this project (or anything Fox might be working on) will actually amount to after the Disney merger, but realistically, this one might also never happen. "Development" is just that, with figures working on turning an idea into something a studio will actually want to spend money on.
If a Kitty Pryde solo movie does move onto the production phase, it'll be interesting to see what the X-Men landscape looks like. Fox currently has three X-Men-related films dropping in 2018: The New Mutants, Deadpool 2, and X-Men: Dark Phoenix. The entire mutant world could be changed forever by the time Kitty Pryde emerges, but we're just hoping if this movie does go down, Pryde's lovable alien dragon, Lockheed, is somewhere in the mix.