PDCD1LG2 and central nervous system cancer: The expression levels of B7-H3, B7-H4, B7-H5, IDO, LAG-3, PD-1, PD-L1, PD-L2, and TIM-3 were significantly higher in glioma samples than in normal brain samples (p < 0.05, Figure 5O), indicating their potential as therapeutic targets.