Multiple myeloma (MM) is an incurable hematological malignancy characterized by progressive immune system dysfunction. Immunotherapy has emerged as a prominent area of research, with various targeted strategies such as monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, chimeric antigen receptor T cells/natural killer (NK) cells, and checkpoint inhibitors being developed. This review discusses the promising experimental and clinical evidence and mechanisms of action underlying these immunotherapies. Specifically, it explores the design of exosome-based bispecific monoclonal antibodies, which offer cell-free immunotherapy options. The treatment landscape for MM continues to evolve with the development of numerous emerging immunotherapies, providing novel perspectives in selecting cutting-edge treatments. Key points include the severe immune system dysregulation in MM patients, the effectiveness of immunotherapy in relapsed/refractory MM, and the potential of immunotherapy in newly diagnosed MM. Open questions include the potential applications of exosome-based bispecific monoclonal antibodies, the effects of immunomodulatory drugs on the MM cellular microenvironment, and the possibility of personalized combinations of immunotherapy drugs for relapsed-refractory patients. The review also covers the mechanisms of action, clinical trials, and future directions for various immunotherapy approaches, including CAR-T cells, CAR-NK cells, checkpoint inhibitors, monoclonal antibodies, antibody-drug conjugates, and bispecific antibodies.Multiple myeloma (MM) is an incurable hematological malignancy characterized by progressive immune system dysfunction. Immunotherapy has emerged as a prominent area of research, with various targeted strategies such as monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, chimeric antigen receptor T cells/natural killer (NK) cells, and checkpoint inhibitors being developed. This review discusses the promising experimental and clinical evidence and mechanisms of action underlying these immunotherapies. Specifically, it explores the design of exosome-based bispecific monoclonal antibodies, which offer cell-free immunotherapy options. The treatment landscape for MM continues to evolve with the development of numerous emerging immunotherapies, providing novel perspectives in selecting cutting-edge treatments. Key points include the severe immune system dysregulation in MM patients, the effectiveness of immunotherapy in relapsed/refractory MM, and the potential of immunotherapy in newly diagnosed MM. Open questions include the potential applications of exosome-based bispecific monoclonal antibodies, the effects of immunomodulatory drugs on the MM cellular microenvironment, and the possibility of personalized combinations of immunotherapy drugs for relapsed-refractory patients. The review also covers the mechanisms of action, clinical trials, and future directions for various immunotherapy approaches, including CAR-T cells, CAR-NK cells, checkpoint inhibitors, monoclonal antibodies, antibody-drug conjugates, and bispecific antibodies.