Why not? Everyone else is a part of the upcoming X-MEN: DAYS OF FUTURE PAST, and Bryan Singer hinted at the possibility of bringing Jean Grey and Cyclops back from the dead.
He was asked if he wanted to get them to appear, and his response was simple:
“Who wouldn’t? Who wouldn’t? That’s all I can say.”
James Marsden and Famke Janssen played Cyke and Jean Grey respectively, but both were killed off in X3. That being said, with time travel afoot in the newest film, a little thing like death would hardly stop Fox and Singer from getting Cyclops and Jean Grey back in the thick of things.
The cast already includes Hugh Jackman, Ian McKellen, Patrick Stewart, James McAvoy, Jennifer Lawrence, Michael Fassbender, Nicholas Hoult, Anna Paquin, Ellen Page, Shawn Ashmore, and Peter Dinklage. We have until July 18th, 2014, to see how it all shakes out.