RecruitingPhase 2Biological interventionLinvoseltamab in Addition to Lenalidomide (L2) During Maintenance Therapy of NDMM to Deepen Responses or Redrive MRD Negativity After RelapseThe purpose of this study is to determine whether giving linvoseltamab with lenalidomide during maintenance treatment to participants with multiple myeloma will: 1. Get rid of any residual multiple myeloma cells in participants' bodies which is known as minimal residual disease negative (MRD-) status. For participants that start the study with residual multiple myeloma cells in participants' bodies: to determine how long you remain MRD-. 2. Increase the length of time that participants' disease is controlled. For participants with relapsed disease, to determine whether participants can re-attain MRD- status. 3. Increase the length of time that participants' disease responds to treatment. The researchers also want to find out the effects that linvoseltamab has on participants and participants' condition.