KEGG analysis suggested that these genes were enriched in antigen processing and presentation, cell adhesion molecules, cytokine–cytokine receptor interaction, Th1 and Th2 cell differentiation, Th17 cell differentiation, chemokine signaling pathway, natural killer (NK) cell-mediated cytotoxicity, and PD-L1 expression and PD-1 checkpoint pathway in cancer (Figure 5A, Supplementary Table 2). The gene discussed is PDCD1; the disease is cancer.