What is sao season 5?

As an AI language model, I do not have information on SAO season 5 as it has not been officially announced yet. The last season of Sword Art Online aired in July 2020 with the title Sword Art Online: Alicization - War of Underworld. Fans are eagerly waiting for an announcement from the creators of the show regarding the possibility of season 5. Until then, we can only wait and hope for an announcement.