In Season 4 of Diablo 4, players will gain access to the Pit of Artificers, a new Endgame mechanic which pits players against the clock while fighting hordes of monsters. Slay enough in time, and you'll gain access to the final boss at the end — a mechanic incredibly similar in form to Diablo 3's Greater Rifts. This content shares a feature that punishes player deaths as well, however this penalty seems to be particularly unforgiving in Diablo 4.
In regards to group play, the time remaining decreases normally upon death, regardless of the number of players. Once a player dies in The Pit, the time penalty resolves immediately for the entire group, and resurrecting your fellow party members will not save your group from losing time. This can be quite a steep penalty for groups trying to carry an undergeared or underleveled member, which may directly influence how parties are formed for the Pit as a whole.