Since HMA treatment did increase the expression of immune checkpoint molecules PD-L1, PD-L2, PD-1, and CTLA4 in MDS and AML patients, a triple therapy combining tumor-specific vaccination peptides, HMAs and immune checkpoint blockade is hypothesized to significantly enhance the anti-leukemia immune reaction [188,189]. The gene discussed is PDCD1; the disease is acute myeloid leukemia.