GTA VI (6) is currently in development at Rockstar, according to an insider leak. So far, the only clues to GTA 6 have been this particular leak and a previous teaser of GTA Online Cayo Perico surveil.exe. Also being speculated is that GTA V could arrive on the upcoming PlayStation VR 2, which could not only boost sales but also make VR a successful platform in upcoming PlayStation generations.
https://www.notebookcheck.net/GTA-6-currently-in-development-Speculative-GTA-V-on-PlayStation-VR-2-could-boost-sales-and-ensure-long-term-platform-success.512988.0.html