Okay so in the game Magik says "Jean and I....we have history" or something to that effect. Huh? When have they ever had history? I cant even recall them ever interacting in the books. Jean was dead by the time Illyana came to the mansion and was aged up to become a New Mutant right after Inferno. She was deaged and shipped back to Russia by the time X-factor became their mentors. The only time I can recall them being in a comic was the issue where Illyana died but Jean spent most of that with Jubilee
By the time Illyana was brought back to the books, Jean was once again dead.Im drawing a blank on what that line could be a reference to. The only thing that could remotely come to mind is AvX when Illyana got the Phoenix Force but that doesnt make sense since Jean was not involved in that arc and definitely did not interact with Illyana