PDCD1 and central nervous system cancer: We found that the several immune checkpoints, including CD274 (p = 1.96 × 10−41), CTLA4 (p = 6.51 × 10−20), HAVCR2 (p = 1.23 × 10−58), LAG3 (p = 6.66 × 10−15), PDCD1 (p = 2.06 × 10−42), PDCD1LG2 (p = 2.86 × 10−62), and SIGLEC15 (p = 1.68 × 10−12), were highly expressed in an APOL4-high group of gliomas (Figure 5A).