Additional Study Information: This study is looking at people who have recently been newly diagnosed with a type of cancer called multiple myeloma (NDMM). The purpose of this study is to learn about the safety, tolerability (how your body reacts to the study drug), and effectiveness (tumor shrinkage) of linvoseltamab (called study drug) in participants with NDMM as a first step in determining if the study drug has a role to play in the treatment of NDMM. This study consists of 2 phases. Your study doctor will tell you which phase of the study you will be participating in. Linvoseltamab is not approved by the U.S. Food and Drug Administration (FDA) or any public health agency for any kind of treatment.