Kevin Feige hasn’t confirmed anything beyond the fact that the mutants will show up at some point down the road, but Chris Claremont is hopeful, telling the NYCC crowd (via AiPT Comics on Twitter)…
Of course, there, is still hope.
With the purchase of 21st Century Fox by Disney, the rights to the characters are now with Marvel Studios and the opportunity now exists for them to be integrated into the existing, and quite successful, Marvel Cinematic Universe.