Recently, IW co-head Patrick Kelly was interviewed by anchor Jackfrags, in which Patrick Kelly said that all future games in the Call of Duty series will be developed using the same game engine.
Patrick Kelly believes that the new engine will be more optimized than the current software tools, and while game studios in the industry want the series not to be too homogeneous, using the same engine to produce will make it easier to integrate game resources in the future.
Currently, the Call of Duty series is led by three studios, IW, Treyarch and Sledgehammer, each using their own game engine.