A new resume listing (via NeoGAF) has suggested Rockstar Games is naturally working on Grand Theft Auto VI.
The resume has actor Tim Neff mentioning his motion capture work on the game, which is has yet to be announced by Rockstar. The actor also lists work for Red Dead Redemption 2, which is coming out next spring.
The latest game in the series, Grand Theft Auto V, first launched back in 2013 for PlayStation 3 and Xbox 360. It was later ported to PS4 and Xbox One in 2014, and even later to PC in 2015.