Australia Revokes Tennis Star Novak Djokovic's Visa Again

Novak Djokovic's visa was canceled for the second time by an immigration official citing public interest. Djokovic had arrived in Australia with a vaccine exemption, but border officials initially rejected it. A judge later overruled this decision, but the visa was canceled again. Djokovic's lawyers plan to appeal. The tournament is set to start Monday, with Djokovic as the defending champion.

What are Djokovic's lawyers expected to do following the visa cancellation?

What is the significance of the tournament mentioned in the text for Novak Djokovic?