Konami has detailed how the save transfer feature will work between MGS5: Ground Zeroes and the upcoming The Phantom Pain.
The Japanese side of Metal Gear Solid publisher Konami has published a handy guide showing how transferring save files will work between Ground Zeroes and The Phantom Pain.
As you can see, save transfers can only work within the same family of consoles, and only from old-gen to new-gen. There doesn’t appear to be an option for transfers across different console families like with GTA Online for instance.
The Ground Zeroes save from the PC version can only carry over to the PC version of The Phantom Pain.