Looking for open-world PvE shooter with 3+ coop

I've recently tried Far Cry 4 coop with a mate, and we are looking for roughly similar game, but allowing 3 or more players in coop.

Here are general conditions:

• 3 or more players co-op, it'd be best if including all content (e.g. single player campaign)

• shooter (FPS or TPS, doesn't matter); stealth options welcome, but not necessary

• open world

• not a MMO; generally we want sth you buy and that's it

• realistic setting: no fantasy, no sci-fi, no zombie apocalypse.

• published roughly between 2014 (older games might look dated and no longer be supported) and 2018 (available cheap on sale)

So far, we are considering Ghost Recon: Widlands (fits all of above), but any other recommendations would be appreciated. Thanks in advance!