Infinity Ward has confirmed that Modern Warfare will have cross-platform play between PC and consoles. As part of the announcement of the game, Modern Warfare cross-platform play was revealed.
Dave Stohl co-Studio Head at Infinity Ward said that cross-platform play was part of an initiative to unite the Call of Duty community.
Other aspects of this initiative include the elimination of the season pass, so players can equally keep pace with new content as it’s released.
Modern Warfare Cross-Platform

Cross-platform play is something that’s not been done in Call of Duty in the past, especially as the releases have aligned themselves with one platform or another. Recently, Call of Duty and PS4 have gone hand-in-hand, but for the longest time it was the domain of the Xbox.
However, as the player numbers on PS4 began to dwarf those on Xbox One, it made sense for Activision to partner with Sony.
The statement from Stohl reads;
We plan for Modern Warfare to be played together across PC and console through cross-play support.

It’s unclear from this statement whether or not PC, PS4 and Xbox One players will be able to play together or if PC and PS4 can play together while PC and Xbox One can also play together.
That runs counter to the idea that Infinity Ward wants to unite the community, however, given Sony’s reluctance to activate cross-platform play, this might be the outcome.
What we do know for certain is that come October 25, when Modern Warfare is released, a lot of PC players are going to be getting very easy kills on controller wielding console players.
Modern Warfare launches on October 25 for PC, PS4 and Xbox One.