RecruitingPhase 2Drug trialImmuno-PRISM (PRecision Intervention Smoldering Myeloma)The purpose of this study is to test the anti-cancer activity of Teclistamab and to compare it with Lenalidomide + Dexamethasone combination in people with high risk smoldering multiple myeloma. People with smoldering multiple myeloma (SMM) usually do not have symptoms but are at risk for progressing to active multiple myeloma (MM). Multiple Myeloma is a cancer of the plasma cells, which are an important part of the immune system. Patients with active multiple myeloma generally require treatment but there are currently no approved therapies for smoldering multiple myeloma. The names of the study drugs involved in this study are: * Teclistamab * Lenalidomide (also called Revlimid) * Dexamethasone (also called Decadron)