User blog comment:Damac1214/CoD Wiki News - February 22nd, 2014/@comment-25494464-20140224001800/@comment-3123696-20140224002959

Avengers and X-Men can't be in a crossover because of legal issues. However, Guardians is part of the Marvel Cinematic Universe, and it's fairly possible that it gets reunited with Avengers, or at least some of the events of the movie.