This study is looking at a new medicine called AZD0120 for people with multiple myeloma (a type of blood cancer). The study will check if the medicine is safe and how well it works. People can join if they are 18 or older and have multiple myeloma. Participants will be divided into two groups: one for those newly diagnosed and another for those whose cancer returned or did not respond to previous treatments.

Key Points:

• The study is open-label, which means both the doctors and participants know which treatment is being given.
• Participants will receive the medicine AZD0120 possibly with other treatments, and the study checks their body's response.
• Participants must not have received certain treatments before, like CAR T-cell therapy, and can't have certain infections or conditions.

This study involves multiple visits to study sites and close monitoring for any side effects. Participants will be helping researchers learn more about treating multiple myeloma with AZD0120.