Does GTA 6 have a single-player campaign?
The direct answer
Yes. GTA 6 ships with a full single-player story following Jason and Lucia — confirmed by Rockstar.
Rockstar has confirmed a single-player campaign as the core of GTA 6, centered on the Jason-and-Lucia crime story across Leonida. A separate online mode is expected to follow rather than replace it.
If you’re worried GTA 6 is online-only, it isn’t: the story mode is the headline experience at launch, exactly as with previous mainline GTA games.