PDCD1 and cancer: Through GO analysis of the development-related genes, we found that their main regulatory pathways involved the MAPK signaling pathway, human T cell leukemia virus 1 infection, Kaposi sarcoma−associated herpesvirus infection, Epstein−Barr virus infection, and PD-L1 expression and PD-1 checkpoint pathway in cancer (Figure 4(c), Table S3, and Table S4).