PD-1/PD-L signaling—dampening of anti-leukemic immunity in AML. PD-L1 and PD-L2 expression on human AML cells at diagnosis and relapse (88). Blocking of PD-1/PD-L1 axis—increase of anti-leukemia immune response and prevention of AML progression in murine model (83, 84, 89). The gene discussed is PDCD1LG2; the disease is leukemia.