The purpose of this study is to compare the usual treatment to using the study drugs, relatlimab and nivolumab in patients with recurrent brain cancer. The use of the study drugs, relatlimab and nivolumab, could shrink or stabilize your cancer. But, they could also cause side effects, which the study team will be monitoring. This study will help the study doctors find out if this different approach is better, the same, or worse than the usual approach. To decide if it is better, the study doctors will be looking to see if the study drugs increase the life of patients compared to the usual...