PDCD1 and myelodysplastic syndrome: Secondly, in addition to patients in first-line or relapsed /refractory setting, PD-1/PD-L1 blockade are also being examined for effectiveness in MDS/AML relapsing after allogeneic hematopoietic stem cell transplantation (allo-HSCT) or individuals at high risk of relapse in NCT03286114, NCT02981914, NCT02532231, NCT03600155, NCT02846376 and NCT02771197.