GTA 5 is now available across all platforms, including the PC. This basically means that the only thing to come next from Rockstar is GTA 6. Then again, fans of the GTA series should not get too excited yet since Rockstar is planning to roll out a series of DLCs to GTA 5.
Once that is done, there is no doubt development on GTA 6 will commence. Even Rockstar agreed on this when they teased on the tons of ideas they have for the upcoming sequel. Of course, the thing that everyone is eager to find out first is the location of GTA 6.
While Rockstar has yet to mention anything on this, the signs are all pointing for the series to return to Vice City. After all, it is the only old GTA location that has yet to receive a modern remake.
If every DLC for GTA 5 is to come out this year, then the chances will be high for GTA 6 to come out in 2017. GTA 6 will be developed based on the Xbox One and PS4, hence, it is going to be massive when released.