The treatment of acute myeloid leukemia (AML) did not evolve profoundly in the last decades. Some improvement has been made for acute lymphoblastic leukemia (ALL). Emerging new treatment modalities, such as immunotherapy, are now beginning to be available for acute leukemia, mostly for patients suffering from ALL. This review aims to give an overview of these new therapeutic approaches, especially those already available. The focus is on cell-based immunotherapy, or molecules using preexisting host cells. Underlying mechanisms are explained and an overview of clinical experience with phase 1-3 studies is given. Immunotherapies discussed are antibody-drug conjugates, bispecific T-cell engagers (BiTEs), chimeric antigen receptor T cells (CARTs) and immune checkpoint inhibitors (ICPIs). Most of the clinical studies reviewed are in ALL patients, usually in the relapse setting, but where available, studies on AML patients were also considered. This new general treatment approach offers hope to patients with until now dismal clinical outcome. Hopes are high that future developments, and moving these therapies to an earlier treatment phase, will improve the prognosis of patients suffering from acute leukemia.