Everybody who was fully vaccinated was made to come back to the office in August of 2021. Those who never vaccinated were allowed to WFH, up until today… and indefinitely. What legalities do I have to demand WFH?

Can I email HR and say I won’t return to the office again until those who are unvaccinated are made to return? I’ve been back in the office for months now, but I’m tired of it. Do they have grounds to fire me for simply not returning to the office every day, and just working from home?