KEGG enrichment results found that DEGs were closely related to immune processes too; for example, PD-L1 expression and the PD-1 checkpoint pathway in cancer, antigen processing and presentation, T-cell receptor signaling pathway, Fc gamma R-mediated phagocytosis, intestinal immune network for IgA production, B-cell receptor signaling pathway, primary immunodeficiency, Th17 cell differentiation, viral protein interaction with cytokine and cytokine receptor, NF-kappa B signaling pathway, TNF signaling pathway, Th1 and Th2 cell differentiation, and chemokine signaling pathway. Here, PDCD1 is linked to cancer.