While Phantasy Star Online 2 is absolutely coming to PC via the Windows 10 operating system, it seems the game's manual reveals that the online action-RPG will make its way to Steam at some point in the future.
The official PSO2 manual gives directions on how to launch the game on various platforms, including Steam. When the game will launch on the platform remains unknown, however, as a cursory search doesn't pull up the game on Steam at the moment. At present, PSO2 is slated to launch on Windows 10 PC and Xbox One between April 1 and June 30.
Phantasy Star Online 2 will kick off its closed Xbox One beta this Friday, February 7. During the short closed beta--which wraps up on Saturday, February 8--you have the chance to earn experience and nab exclusive in-game rewards, all of which will carry over to the full game when it launches this spring.
The popular online action-RPG made an appearance during Microsoft's E3 2019 press conference, where Xbox boss Phil Spencer confirmed that Phantasy Star Online 2 won't be exclusive to the Xbox brand. Further, it has been revealed that, though temporarily exclusive to Microsoft's platforms, PSO2 won't be region locked.