CD8A and breast cancer: Recently, increasing evidence has indicated that the immunological status of T cell subsets provides better prognostication than CD4+ or CD8+ T cells in cancer patients, e.g., AML patients who express a higher percentage of PD-1+Tim3+CD8+ TCM cells are prone to relapse, and the prognosis of breast cancer patient with a higher number of CD8+ tissue residual memory T (TRM) cells was better (14, 15).