Phantom Pain on PC. Maybe.
Presently Metal Gear Solid 5: The Phantom Pain has only been confirmed for PS3, PS4, Xbox 360 and Xbox One with nothing confirmed for the PC crowd. However, that may change if what Hideo “Frickin’” Kojima has said recently is anything to go by. Kojima recently told Gamespot "PC, that's my original background. I originally created PC games. A long time ago I didn't want to rely on platforms to release games, so if people want it, I cannot make a formal announcement, but that is definitely something that I would like to do."
If it’s something even the series creator wants then the possibility seems more than likely.
That said, MGS 4 never saw release on PC though its spin off centred on a cybernised Raiden, Metal Gear Rising: Revengeance, did. However that was 11 months after console release. Hopefully, if we see The Phantom Pain on our platform of choice at all, we won’t be waiting quite as long.