PDCD1 and glioma: Our results showed that there was a positive correlation between risk score and the expression of PDCD1, CD274, PDCDLG2, CTLA4, CD80, and CD86. In addition, we found that risk score was significantly associated with TMB, including several common somatic mutations (TP53, PTEN, and EGFR) in glioma (Segura-Collar et al., 2020).