T-cell-engaging antibodies (TCEs) are synthetic molecules that redirect T cells to bind to the antigens on the surface of cancer cells to promote tumor elimination. In the case of multiple myeloma (MM), the approvals of anti-CD38 monoclonal antibodies (MAbs), chimeric antigen receptor T-cell therapies (CAR T) targeting B-cell maturation antigen (BCMA) or, more recently, bispecific TCEs represent great advances, but some patients still relapse after treatment.