CD8A and central nervous system cancer: Improved survival was observed in GL261 glioma-bearing mice treated with anti-PD-1 therapy combined with radiotherapy and was correlated with higher infiltration of cytotoxic T cells (identified as CD8+ IFNγ and TNFα double-positive) and a lower frequency of Tregs (characterized as CD4+ FoxP3+) compared with those in the single modality arm (anti-PD-1 therapy) [44].