NBA players who live in markets with vaccine requirements must be vaccinated in order to play at home.
Because San Francisco has local government requirements regarding the COVID vaccine, Warriors players will not be able to play inside the Chase Center if they are unvaccinated. Shams Charania reports that this only applies to the home team and visiting players will be exempt.
New York is another market with vaccine requirements.
San Francisco's vaccine mandate went into effect on August 12th.
More information available here.