CD8A and neoplasm: Recently, classifications based on the TME have emerged; for example, three distinct lymphocyte infiltration modules have been identified as follows (21–23): (i) the inflamed/infiltrated phenotype, in which CD8+ T cells infiltrate the tumor epithelium; (ii) the excluded phenotype, in which infiltrating CD8+ T cells accumulate in the tumor stroma rather than the tumor epithelium; and (iii) the immune desert/ignored phenotype, in which CD8+ T cells are either absent or present in very low numbers.