The recent phase II clinical trial in patients who undergo human leukocyte antigen–matched unrelated donor allogeneic hematopoietic stem cell transplantation, CD24-Fc treatment has been shown to significantly prevent acute graft-versus-host disease (GVHD development with no unexpected drug-related immunotherapy-related adverse events (irAEs) or toxicities observed [34]. The gene discussed is CD24; the disease is graft versus host disease.