Takes place in the future. Main city is a gigantic metropolis divided by the poor and incredibly rich. Imagine Blade Runner mixed with Fallout. City is the size of Los Santos or Liberty City. Game starts out with missions in the city. Main character gets framed for murdering a politician, to stay in the city and not be exiled they have to hunt and kill/bring in the murderer.
At that point you leave the city to explore the outside world. Outside world is all beautiful wildlife and nature, inhabited by gangs and crazy cults. Tons of animals, tons of vegetation variety. You explore and have to survive in this world (hunger and sleep matter).
No kidding, a game called The Red, The Dead, and the Ugly, where you hop characters GTA V style, would be pretty fucking fun.
The Red: A Native American protagonist trying to live right even though the entire country is trying to marginalize him
The Dead: A former slave with a MASSIVE bounty on his head after killing his master and running.
The Ugly: A Jonah Hex-esque disfigured drifter with a mysterious past.