Depending on the nature of the tumor, the immune component may be composed by cell populations with diverse functional activities, including: myeloid cells (neutrophils, macrophages, antigen-presenting cells (APC)), lymphocyte subsets such as Th-17 and Th-1 cells, follicular T helper lymphocytes (Tfh), regulatory T cells (Tregs), CD8+ cytotoxic cells, and B cells. This evidence concerns the gene CD8A and neoplasm.