Final Fantasy XVI was early on confirmed to be a six month time-exclusive title for PlayStation 5, but nine months later, we still haven't heard anything about the PC version. Fortunately, this might change fairly soon, as producer Naoki Yoshida says to Game Informer that the PC version of the game currently is in "the final stages of optimization".
It seems like you might need a beefy computer to play it though, as he also admits in the same interview that the system requirements are "looking to be somewhat high" - which frankly shouldn't be too surprising for anyone who has played the game.
Besides the PC version, the developers are currently also working on The Rising Tide, which is the second major DLC for Final Fantasy XVI, and planned to be released this spring.