Far Cry 1&2 are strictly solo advantures. Far Cry 3 has a sperate co-op mode, but the main campaign can only played solo. Far cry 4's world can be traversed cooperatively, but the story missions cannot be played through with a partner. The only Far Cry games that can be fully experienced in co-op are 5 and New Dawn. 4.
In Far Cry 5 it is possible to play alongside a friend in online co-op mode! You will be able to access multiplayer features once you have left Dutch's Island. Console players will require an active PlayStation Plus or Xbox Live Gold membership to access co-op features.
How Many People Can Join in Co-op Mode? You Can Only Add One Player. In Far Cry 6's Co-op mode, you can only add one extra player to join you during the game. Similar to previous Far Cry games, the Co-op experience is limited to 2 people at a time, providing you with a friend that can help you complete missions and liberate military targets