V-r0cK on 24 March 2018
There's only a few reasons I can think of as to why its only campaign:
1. People love the MW storyline more so than the multiplayer (cause we dont see any other CoD games getting this treatment)
2. Activision doesn't want to split up the community. They just want to keep it simple so that every year they release one new CoD and focus on that MP rather than have them branching that could cause more of a headache. That would just cause internal conflict between the games.
