This review summarizes current advances in CAR-NK cell therapy for MM, focusing on two major aspects: the diversity of cell sources—including NK-92, peripheral (PB) and cord blood (CB), and induced pluripotent stem cell (iPSC)-derived NK cells—and the expanding repertoire of target antigens such as BCMA (B-cell maturation antigen), NKG2D, CD38, CD70, SLAMF7, CD138, and GPRC5D. Here, GPRC5D is linked to Miyoshi myopathy.