In AML, this immunological block is due to the fact that despite the presence of a similar number of CD4+ CD8+ T lymphocytes in the leukemic and normal bone marrow (BM), the expression of ICP receptors is higher on T cells contained in the leukemic BM than on T cells contained in the healthy BM [49,50,51]. The gene discussed is CD8A; the disease is acute myeloid leukemia.