Based on CCR7 expression (16), a marker for TCM with migratory capacity to secondary lymphoid organs (SLO) (17), a median of 27.37% (0.53%-99.22%) of CD8+ T cells and 31.98% (0-90.96%) of CD4+ T cells in HCC had a TCM phenotype; In PDA, 12.61% (0.26%-80.13%) of CD8+ T cells and 21.32% (0-56.97%) of CD4+ T cells had a TCM phenotype; In CCA, 13.17% (0.68%-14.85%) of CD8+ T cells and 20.29% (0.22-43.58%) of CD4+ T cells were TCM. The gene discussed is CD8A; the disease is hepatocellular carcinoma.