This study is testing four medicines for people with a type of blood cancer called relapsed refractory multiple myeloma. Relapsed means the cancer has come back after treatment. Two parts of the study will test different mixes of the medicines to see if they are safe and how people feel when taking them. The medicines are given in 4-week cycles and will be tested for about 2 years.

• The study involves getting medicine as a shot or through an IV (a tube in your vein).
• You need to have multiple myeloma and have tried other treatments before.
• Participants must agree not to get pregnant or breastfeed during the study.

In Part 1, participants will get a shot of elranatamab and an IV of carfilzomib and dexamethasone. In Part 2, participants will get elranatamab and maplirpacept through an IV. The study will help doctors learn if these medicines can be used safely to help treat multiple myeloma. Only people who meet certain health conditions and have had a specific number of previous treatments can join. They must also be willing to use birth control to avoid pregnancy during the study.