Hideo Kojima is in Metal Gear Solid V - The Phantom Pain -
To unlock him, you have to play MGSV Ground Zeroes.
Play the side ops mission : Intel Operative Rescue
In this mission you rescue Hideo Kojima.
Upload your save to the cloud in Ground Zeroes and download it to The Phantom pain for him to join your team.
Metal Gear Solid V: The Phantom Pain Statistics For ZWGamemaster
ZWGamemaster currently has 51,480 views spread across 73 videos for Metal Gear Solid V: The Phantom Pain. Roughly a days worth of Metal Gear Solid V: The Phantom Pain videos were uploaded to his channel, roughly 1.23% of the content that ZWGamemaster has uploaded to YouTube.