Back before the 2020-21 college basketball season started, the NCAA announced that all winter sports athletes would be extended an extra year of eligibility. At its heart, the policy intended to advise the winter sports athletes that if they wished to sit out the 2020-21 season due to health concerns related to the COVID-19 pandemic, they could and still play their four years worth of eligibility. If you played during the 2020-21 season, you still get the extra year anyway for a fifth season of competition.
If you’re a redshirt senior and you want to return to school for a sixth year of college, then you can do that, too.