Although Warhammer 40K: Space Marine 2 includes a full campaign in which players fight against Tyranids, and the game also offers a PvP (player versus player) mode, it seems that the game fits logically into PvPvE (player versus player versus environment), however. there is nothing like it in the game.
For those wondering if we can expect this in future updates, developer Saber Interactive has confirmed that it has no plans for it. Game director Dmitry Grigorenko said:
PvPvE is the Holy Grail of game design. Many studios try to find it, and many of them fail. The truth is that this is very, very difficult work. It sounds great on paper, but when you start doing it, it becomes obvious that it’s very annoying when you fight with other players and then get stabbed in the back by an AI opponent. That’s why most games try to make sure that the PvP and PvE aspects don’t overlap too much, ie AI opponents are limited to certain places on the maps, etc. This is a difficult mod to implement and will change the game a lot, so I’m afraid we have no plans for it.
In the same interview, Saber also mentioned that they could have made Space Marine 2 an open world game, but they didn’t think fans would like it.