PDCD1 and central nervous system cancer: By conducting Pearson correlation analysis on glioma samples from the CGGA and TCGA databases, it was discovered that the expression of SOCS1 is significantly positively correlated with several known inhibitory immune checkpoints, including HVEM, TIM-3, PD-1, PDCD2, TIGIT, CD200R1, CTLA4, and CD47.