Will GTA 6 be on Game Pass?
The direct answer
Not at launch, and unconfirmed beyond that. GTA 6 is a paid release, and no Game Pass deal has been announced.
GTA 5 did eventually reach Xbox Game Pass, but that came years after launch via a time-limited deal. A brand-new Rockstar tentpole going straight to Game Pass on day one would be unprecedented.
Expect to buy GTA 6 outright at release. A later Game Pass appearance isn’t impossible given GTA 5’s history, but nothing has been announced.