Horizon: Zero Dawn and The Last of Us were both surpassed by Bloodborne.
Sony revealed the most-played PS Now games for the period between March 1 and June 1, 2021, via the PlayStation Blog. To no one's surprise, Bloodborne was at the top, Horizon: Zero Dawn came second and The Last of Us came third. For anyone who doesn't own a Playstation, using PS Now is currently the only way to play Bloodborne. Given that and the game's enduring popularity, it's no surprise it topped the list.
For those of you who don't know, PlayStation Now is a game streaming subscription that allows users to play different PlayStation games on PlayStation 4 and 5, as well as PC, offering games from the PS2 era to some of the PS4's biggest titles. While some PS Now games have PC ports, like Horizon: Zero Dawn, PS Now lets you play games even if your PC hardware isn't fit for handling the port.