There is a recent update that is coming on PS4. This update is going to add a new feature that will let players to copy Metal Gear Solid V: Ground Zero save game files in Metal Gear Solid V: The Phantom Pain. By doing this players can unlock a variety of things and play the game. This feature will be available through Patch 1.01 once it is added in the game. And then you get an option through which you can just add your Save Data in the new game and enjoy some new things unlocked.
This unlock includes some in-game costumes and also some soldiers that you have extracted in Ground Zeros, to your Mother Base in The Phantom Pain. After adding the patch you will find the option in the main menu itself. You can then add the save game and transfer that. You must have Ground Zero installed and completed in order to use this feature. Once the save game is moved then you can get a few recruits of Mother Base. You have to download this data from the game menu.
Right now this feature is only provided for PS4 and it will come on Xbox One today. So you can test the same in the Microsoft console also. If you had played the PS3 version of Ground Zero then you can still add that in PS4 and test out the gameplay. It is possible to update the save game file from PS3 to PS4 but not to Xbox One. You will need the same console here. You just have to upload the save game file from the menu. Once you are done with that you can then go in the menu and then click on Download Save data.