The first trailer confirms that the game is coming back to Vice City, and a new female character will be one of the main protagonists. Although the game does not show a lot of details, it does look pretty impressive.
Rockstar has also confirmed that the game will be coming in 2025, with no fixed date. It is launching on Playstation 5 and Xbox Series X/S, which probably means that the PC version will come at a later date, similar to GTA V. GTA V launched in September 2013 on consoles, and only came to the PC in April 2015. This also means that Rockstar will have plenty of time to polish the game.
In any case, here is the GTA VI trailer.