• Age \> 18 years.

• Histologically confirmed diagnosis of multiple myeloma with evidence of progressive disease as defined by the IMWG criteria.

• Have measurable disease, defined as:

∙ Serum M-protein level ≥ 1.0 g/dL, or

‣ Urine M-protein level ≥ 200 mg/24 hours, or

‣ In patients without a measurable M-protein, an involved light chain level ≥ 10 mg/dL and an abnormal free light chain ratio.

• Patient had at least one prior line of therapy (PLOT), including a proteasome inhibitor (PI), an anti-CD38 antibody, and an immunomodulatory drug (IMID).

• Patient meets the requirements for the use of talquetamab, as per the most recent FDA prescription information.

• Patient plans to receive cilta-cel and meets the criteria for commercial use as per the most recent FDA prescription information.

• Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at screening.

• Have the following clinical laboratory values at screening:

• Adequate bone marrow function:

• Hemoglobin\* ≥ 8.0 g/dL; Absolute Neutrophil Count\* ≥ 1,000/mcL; Absolute Lymphocyte Count\* ≥ 200/mcL; Platelets\* ≥ 25,000/mm\^3

• \*Transfusion and growth factor support within 72 hours allowed.

• Adequate hepatic function:

• Total Bilirubin \< 2 mg/dL; Aspartate aminotransferase (Serum Glutamic Oxaloacetic Transaminase)/Alanine Aminotransferase \< 5 times institutional upper limit

• Adequate renal function:

• Creatinine Clearance ≥ 30 mL/min/1.73 m\^2 for patients with creatinine levels above institutional normal

• Female patients must meet one of the following:

∙ Postmenopausal for at least one year before the screening visit, or

‣ Surgically sterile, or

‣ If they are of childbearing potential:

• i. Agree to practice two effective methods of contraception from the time of signing of the informed consent form through three months after the last dose of the study drug, AND ii. Must also adhere to the guidelines of any treatment-specific pregnancy prevention program, if applicable, or iii. Agree to practice true abstinence when this is in line with the preferred and usual lifestyle of the subject. (Periodic abstinence \[e.g., calendar, ovulation, symptothermal, postovulation methods\] and withdrawal are not acceptable contraception methods.)

⁃ Male patients, even if surgically sterilized (i.e., status postvasectomy), must agree to one of the following:

• Practice effective barrier contraception during the entire study treatment period and through 90 days after the last study drug dose, OR

∙ Must also adhere to the guidelines of any treatment-specific pregnancy prevention program, if applicable, OR

∙ Agree to practice true abstinence when this is in line with the preferred and usual lifestyle of the subject. (Periodic abstinence \[e.g., calendar, ovulation, symptothermal, postovulation methods\] and withdrawal are not acceptable methods of contraception.)

⁃ Ability to understand a written informed consent document, and the willingness to sign it.