PDCD1 and glioblastoma: Consistently, flow cytometric analysis of GBM tissues also showed that deletion of ALKBH5 with anti-PD-1 Ab treatment provided the most significant number of infiltration T cells (CD3+, CD4+, and CD8+ T cells) and notably increased the ratio of CD8+ /CD4+ T cells to the highest level among these four groups (Fig. 3G–K).