This is not the way it'll play out but assuming it'd be a trade vis a vis to get "X" exclusive game from Playstation for "Y" COD game then if I'm Microsoft I'm picking Spider-Man, Wolverine, and KOTOR. Those are just licenses that Sony holds with an expiration date. MS can play the long game, get the fans of those franchises on XBox and reach out to the IP holder for a licensing deal later. Plus those are probably the most popular ones as is and every other big exclusive franchise is actually owned by Sony.