Just wanted to let everyone know before this launches, cross-platform invites will not be available at launch, and probably not even planned according to the official response, so make sure you're getting this on the same platform as anyone else you plan on playing with. Matchmaking will still make use of other platforms' players, but we cannot invite cross-platform (e.g. Player 1 on Steam cannot invite Player 2 on PS5 to party, only other Steam players).

Player pool 1: Xbox One, Xbox Ser. X, Xbox Ser. S, PC MS Store/Gamepass

Player pool 2: PS4/PS5

Player pool 3: Steam

Source: https://www.reddit.com/r/exoprimal/comments/14jxalx/cross_party_is_confirmed_not_to_be_present_at/