Inclusion Criteria:

1. 18 years or older
2. Provides voluntary written informed consent
3. Relapsed or refractory multiple myeloma (MM) following treatment with a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody
4. Measurable disease following completion of most recent anticancer therapy
5. No serious concomitant diseases or active/uncontrolled infections
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
7. Adequate organ function

Exclusion Criteria:

1. Plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS syndrome, or primary AL amyloidosis
2. Solitary plasmacytomas without evidence of systemic disease
3. Women who are pregnant or breastfeeding
4. Current isolated central nervous system (CNS) involvement
5. Prior allogeneic bone marrow transplant, gene therapy, or adoptive cell transfer (except tumor-infiltrating lymphocytes, CAR-NK cells, T-cell receptor [TCR] fusion constructs, TCR T cells, and CAR T cells)
6. History of or active human immunodeficiency virus (HIV)
7. Active or chronic hepatitis B, or active hepatitis C
8. Systemic immunodeficiency diseases, except for well-controlled Type I diabetes or thyroid disease
9. Ongoing CNS disease that would preclude neurologic assessment
10. Uncontrolled angina or other acute heart disease
11. Currently receiving treatment in another interventional clinical trial.