To assess the impact of ICI on T-cell accumulation and CD69 expression in vivo, mice bearing GL261 GBM tumors were treated with anti–CTLA-4 and anti–PD-1 ICI (200 μg per Ab per mouse; i.p.)or vehicle control on days 10 and 12 after tumor cell inoculation. Here, PDCD1 is linked to glioblastoma.