Hideo Kojima has confirmed in the French magazine, IG, that “Metal Gear Solid 5″ is in the works and will be using the Fox Engine. On top of that, he has stated that Solid Snake will be in the game.
Kojima also stated:
About Metal Gear Solid 5, I can tell you two things. There will be much question of infiltration, espionage, and convincing people to give you ‘a favour’ like in the last Metal Gear Solid.
Apparently, MGS5 will include more interaction and decision making with NPCs unlike ever before. If hints from his past interviews come to fruition, the game may very well take place in Normandy, France.
This is still a developing story and we will bring more details as they come in.