Rockstar Games, the developer behind the Grand Theft Auto and Red Dead Redemption franchises, won't release another game until the next fiscal year, meaning April 2017 at the earliest. The announcement was made at the earnings call of their parent company, Take-Two Interactive, where CEO Strauss Zelnick stated that "Rockstar will not release a new game in the current fiscal year." While a new game is a long ways off, Take-two has indicated that an announcement regarding one is coming soon.
Though Rockstar has yet to confirm anything, a new Red Dead Redemption game has been rumored for some time. The must recent suggestion of this was the supposed leaking of the game's map, which surfaced in April.