Christoph Schmid, MD, University of Augsburg, Augsburg, Germany, comments on the use of donor lymphocyte infusion (DLI) in relapse management. Dr Schmid reports that results from the PRO-DLI Phase II prospective trial (NCT02856464), assessing whether prophylactic donor DLI improves the disease-free survival of patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), are eagerly awaited. This interview took place at the 2021 Relapse After HSCT² Workshop in New York, NY.