User blog comment:Argorrath/Activision confirms next Call of Duty for this year/@comment-5596583-20130214005513/@comment-67.247.72.112-20130219093448

They did! Sledgehammer is reportedly working on the current title, Treyarch planned for the 2014 release, and IW working on something.

All rumors I suppose, but I'd be willing to bet IW is working on a next gen title, and has a 3 year dev cycle.