One of the new additions to the Steam database clearly shows that Returnal is coming to PC.
Added to SteamDB under the Oregon codename, the game’s labels include words like “rogue-like,” “sci-fi,” and “bullet hell.” There are so many games with these labels,” and you’re right. But again, the references to Tower of Sisyphus and Atropos in the database reveal that this is beyond doubt Returnal.
Tower of Sisyphus is the name of the infinite mode in Returnal. You climb the tower of this name and fight against the waves of enemies that are getting stronger and stronger.
Atropos is the name of the alien planet that the game is set on.
VGC reports that one of its sources shared a video with them showing that Returnal was working on PC.
Returnal was also one of the games on the leaked GeForce Now list. If you want to remember that list , you can look it here.