Will this have online multiplayer?

[Auditect]

Since there is an in-game co-op mode and it's on Steam, I think it would make sense if I could play it with friends on Steam.

[Microsoft Excel]

Not sure about it having built in online coop but if there isn't, you can always try Remote Play Together

[VirusURABUMHOLE666]

On the steam page, it does say there's split-screen and Couch gaming, so it's gonna be the "Remote play" with friends.