Back in August, developer 343 Industries confirmed that cross-platform play would be coming to The Master Chief Collection.
According to PC Gamer, the test build of Halo 4 supports cross-play between PC and Xbox One in traditional multiplayer modes, Forge, and Firefight. Campaign and Spartan Ops co-op is excluded — at least for the time being.
For most modes, the Master Chief Collection’s matchmaking will separate players by input type — keyboard-and-mouse players from controller players, basically.
“With input-based matchmaking and cross-play, the goal is to break down as many barriers between players as possible, but to split players by something that has a direct impact on their moment-to-moment gameplay experience,” technical designer Dana Jerpback said in August.
“In a playlist like Infection, when cross-play and input-based matchmaking features come online, we’re not going to limit by input at all. The same can be said for something like Firefight. We don’t believe that there is a need to lock players by input in these areas.”
From the sound of things, we can probably expect to see Halo 4 PC and cross-play functionality going live sometime in November.