A Study of CT0596 in Relapsed/Refractory Multiple Myeloma and Relapsed/ Refractory Plasma Cell Leukemia

1. Pregnant or lactating women; 2. Patient has any significant condition(s), laboratory abnormality or psychiatric illness that would impair the ability of the patient to receive or tolerate the planned treatment or in the opinion of the investigator, participation would not be in the best interest of the patient (eg, compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments 3. Patients seropositive for HIV, active hepatitis C virus (HCV), or active hepatitis B virus (HBV) infection. History of treated hepatitis B or C is permitted if the viral load is undetectable per qPCR and or nucleic acid testing; 4. Patients with any uncontrolled active infection, including but not limited to patients with active tuberculosis (investigator 's judgment); 5. Toxicities caused by previous treatment have not recovered to Common Terminology Criteria for Adverse Events (CTCAE) ≤ Grade 1, except alopecia and other events that are judged tolerable by the investigator; 6. Previous allogeneic stem cell transplantation; autologous stem cell transplantation within 12 weeks prior to signing informed consent; 7. Have received treatment for the disease within 14 days before informed consent 8. Have received cell therapy within 28 days before informed consent. 9. Systemic glucocorticoids equivalent to > 15 mg/day prednisone within 7 days prior to informed consent, with the exception of topical glucocorticoids; 10. Vaccination with live attenuated vaccines , inactivated vaccines or RNA vaccines within 4 weeks prior to informed consent; 11. Allergic or intolerant to lymphodepletion, tocilizumab, or allergic to components (DMSO) in CT0596 CART cell infusion preparation; or previous history of other serious allergies such as anaphylactic shock; 12. Patients with secondary plasma cell leukemia, Waldenström macroglobulinemia, POEMS syndrome, or primary light chain amyloidosis at Screening; 13. Patients with any of the following cardiac conditions within 6 months prior to screening: 14. Patients who require supplemental oxygen to maintain oxygen saturation > 92%; or Patients with known or suspected COPD who have Forced Expiratory Volume in 1 second (FEV1) < 50% of predicted normal on spirometry; 15. Patients with active autoimmune diseases, including but not limited to psoriasis, rheumatoid arthritis and other diseases requiring long-term immunosuppressive therapy; 16. Patients with second primary malignancies in addition to MM are not eligible if the second primary malignancy has required treatment within the past 2 years or is not in complete remission. Exceptions include the following that have been successfully treated - nonmetastatic basal cell or squamous cell skin carcinoma, non-metastatic prostate cancer, carcinoma-in-situ of breast or cervix, non-muscle invasive bladder cancer 17. Patients with symptomatic central nervous system (CNS) disease or suspected CNS metastases; 18. Major surgery within 2 weeks before informed consent or planned during the study period or within 4 weeks after giving study treatment (excluding local anesthesia such as cataract)