Grand Theft Auto VI is an confirmed but currently unreleased game, possibly developed by Rockstar Games. It will be the sixteenth title in the Grand Theft Auto Series. Most likely it will be released for the Xbox One, PlayStation 4, and PC, and possibly the Nintendo NX.
A rumor has it that it will return to Vice City, and other rumors have it that it will be either London, or an entirely new city altogether. Another rumor has it that Rockstar has been thinking about combining all cities from the previous games (Liberty City, Vice City, Los Santos and possibly others).
More rumors suggest that if the game does in fact, return to Vice City, it will be set in the 1980s, while others suggest it will be set in modern day. These rumors are not confirmed.
Some other rumors speculate the game will be set in modern-day Mexico, dealing with drug-dealing, gangs, and illegal immigration.