A Study to Compare Linvoseltamab Monotherapy and Linvoseltamab + Carfilzomib Combination Therapy With Standard-of-Care Combination Regimens in Adult Participants With Relapsed/Refractory Multiple Myeloma (RRMM)

This study is researching a drug called linvoseltamab (also called \"study drug\") either given alone or in combination with another anti-myeloma drug called carfilzomib, compared to several standard treatments for progressive Multiple Myeloma (MM) after at least 1 but no more than 3 prior therapies. The aim of this study is to see if the safety and efficacy of linvoseltamab alone or in combination with carfilzomib can deliver better outcomes (deeper and longer responses that help extend life) than standard treatment options. The study is looking at several other research questions, including: * What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)