To Evaluate the Safety and Efficacy of Human BCMA Targeted CAR-NK Cells Injection for Subjects With R/R MM or PCL

This study tests a CAR-T cell therapy that targets a protein called BCMA, which is found on the surface of myeloma cells. It is designed for patients with multiple myeloma (a blood cancer) that has come back or stopped responding to previous treatments. **You may be eligible if...** - You are 18 or older - You have multiple myeloma confirmed by lab testing - Your BCMA protein levels meet the required threshold - You have received prior standard treatments that are no longer working - Your organ function (kidney, liver, heart) is within acceptable limits **You may NOT be eligible if...** - You have active serious infections - You have had prior BCMA-targeted CAR-T cell therapy - You are pregnant or breastfeeding - You have uncontrolled heart disease or serious organ failure Talk to your doctor to see if this trial is right for you.