PDCD1 and cancer: ARL4C exhibited a positive correlation with various immunosuppressive genes, namely TIGIT, TGFBR1, TGFB1, PDCD1LG2, PDCD1, LAG3, IL10, IDO1, HAVCR2, CTLA4, CSF1R, CD96, CD274, CD244, BTLA, and ADORA2A, across multiple cancer types including ACC, BRCA, and COAD (Figure 7C).