Insider Dusk Golem previously mentioned that Resident Evil 9 was initially intended to be a cooperative game, but the concept was revised during development.
The result was Resident Evil Requiem, which became a regular single-player game.
Recently, a compilation of footage from the "cooperative Resident Evil 9" was published online. Game director Koshi Nakanishi explained the rejection of this version by saying that "this is not what our fans would want to play."