Rockstar Games are probably still a long way from releasing GTA 6 so they simply announced improvements for GTA V during the PlayStation 5 event, as well as a bunch of free money for the PS4 players.
Grant Theft Auto V will get enhanced for next-gen consoles but some details on whether the upgrade will be free for owners on PS4 remain dubious. Rockstar confirmed that the enhanced version is coming in the second half of 2021 so we are still about a year out from its release.
Players will find "a range of technical improvements, visual upgrades and performance enhancements" on the new generation of consoles but the one thing on everyone's mind is the loading screen. Considering the SSD capabilities of PlayStation 5, these should be reduced drastically compared to PS4 although Rockstar didn't explicitly confirm this.
Similarly, they didn't confirm intergenerational cross-play as the journey through the "shared world of GTA Online will continue on to the new generation", hinting that it will not be connected with the current-gen consoles.
Furthermore, some new updates to GTA Online will be "exclusive to the new consoles and PC", so the current-gen version is pretty much going to be left behind.
There will also be a standalone version of GTA Online coming out at the same time and PlayStation 5 owners will have three months to claim it for free. It will be a paid addition afterwards.
Finally, the PlayStation Plus members who enjoy GTAO on PlayStation 4 will get GTA$1 million each month, provided they log in at least once a month. This promotion will continue until the launch of GTA Online on PS5.