Based on the TCGA-GBM dataset, we further explored the expression of immune checkpoints, including PDCD1, PDCD1LG2, CD274, CTAL4, HAVCR2, and LAG3, and found that PDCD1LG2 (p < 0.0001), CD274 (p = 0.0011), and CTLA4 (p = 0.011) were upregulated in GBM patients with a higher expression of GPX8 (Figure 7E). The gene discussed is PDCD1; the disease is glioblastoma.