When you're approaching a movie sequel, you sort of expect some level of continuity. You'd expect the general shape of the story to reflect what came before, for the tone and spirit of the original to continue and for the characters you left at the end of the first chapter to return too.
Unfortunately, that's not always possible, and through a combination of scheduling conflicts, real-world influences or people just not wanting to return (or not being welcome), some actors end up recast or on the scrapheap by the time the sequel comes around. Occasionally, the films actually reference their departures, but that's not even always the case.
Whatever the reason behind it, you won't be seeing these actors in forthcoming sequels...
10. Olivia Munn - X-Men: Dark Phoenix
Don't expect to see Psylocke in X-Men: Dark Phoenix. Despite the fact that the character - played by Olivia Munn - escaped the plane crash that killed Angel in Apocalypse with her life and evaded the X-Men, she won't be popping up to fight them again. Or indeed join them.
Munn has confirmed she's not returning to ET Canada as well as revealing that she's had her wrist slapped for sharing secret information previously on the project (which all turned out to be wrong) including her return:
“I can’t say anything because last time I said a little bit they sent me a note. But I’m not in it.”
Apparently, she was busy filming The Predator and her schedule wouldn't allow her to appear in Dark Phoenix too.
What It Means For The Film:
Munn's performance was completely fine without being particularly spectacular, but there was some controversy over the decision to put her in a comics accurate costume, given how... sexualised her look has always been.
In narrative terms, the fact that she's a loose end is slightly frustrating, but there was some suggestion she might be turning up in an X-Force movie, so perhaps that was the original thinking? Probably not now though, what with Disney buying Fox's Marvel characters back and kicking off their own plans...