Theoretical relative therapeutic potential of cellular therapies for relapse. The shaded quadrant represents the zone of optimal specificity with respect to tumor vs off-target cytotoxic tissue damage, which maximizes antitumor potency and minimizes cell-mediated morbidity. Conventional DLI and second SCT (depicted in red) are the currently available cell-based treatments for relapse, against which novel therapies (blue) will be judged. CAR, chimeric antigen receptor; CIK, cytokine-induced killer; DLI, donor lymphocyte infusion; MiAg, minor histocompatibility; NK, natural killer; SCT, stem cell transplantation; TAA, tumor-associated antigen. Reprinted from de Lima et al⁵  with permission (published under the terms of the Creative Commons attribution–noncommercial–no derivatives license [CC BY NC ND]).