As part of the Call of Duty: Modern Warfare reveal, Activision confirmed that cross-play will be introduced in the franchise for the first time. For those worried about being at a disadvantage against another player using a mouse and keyboard, youll be happy to learn that the matchmaking system will be based on the input of the device you use.
Source: N4G PC Call of Duty: Modern Warfare Cross-Play to Be Based on Input Matching