Tennis is a real racket sport played one on one or in doubles across a court divided by a net, scored in games and sets, with control coming down to timing, placement and power. GTA 5 already had its own version, a timing based minigame at courts around Los Santos. Leaked material points to it coming back in GTA 6, set on courts at Leonida's country clubs and public parks. If it returns the way it worked before, expect swings that reward good timing and shot placement over button mashing. Rockstar has not confirmed tennis for GTA 6 at all, so its presence, its exact courts and how it controls are all leak based expectations rather than announced features. It sits with the other returning activities leaks describe rather than anything shown on screen so far.
The community companion for Grand Theft Auto VI. Database, maps, guides and tools for Vice City and the state of Leonida.