CD7 and graft versus host disease: To explore the efficacy and safety of CAR-T therapy in the treatment of relapsed/refractory hematological malignancies, as well as the effective prevention of GvHD in the absence of conventional conditioning chemotherapy, a trial of CD7 CAR-T therapy followed by haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) was conducted in patients with CD7-positive acute leukemia.