The PA Report has confirmation from Microsoft Game Studios that
Halo 4 is not coming to the PC, which isn't too surprising considering Halo 3 was never ported to the PC either. What's a little odd is the explanation, as a spokesperson tells them: "Halo 4 was designed specifically for Xbox 360, and while we’re always exploring new ways to expand the franchise and share the Halo experience with as many fans as possible, we do not currently have any plans to port Halo 4 to PC."