GSEA showed that the immune-associated pathways were most active in subtype 3, and consisted of Th17 cell differentiation, NF-κB signaling axis, the B cell receptor signaling cascade, the T cell receptor signaling cascade, PD-L1 expression and the PD-1 checkpoint axis in cancer, the IL-17 signaling cascade, and the tumor necrosis factor (TNF) signaling axis. Here, PDCD1 is linked to cancer.