This modular study aims to evaluate the safety, tolerability, cellular kinetics, pharmacodynamic effect, immunogenicity, and preliminary efficacy of AZD0120 in subjects with newly diagnosed or early relapsed or primary refractory multiple myeloma. Module 1 consists of early line MM (including newly diagnosed MM and early relapsed or primary refractory MM) with AZD0120 (for newly diagnosed multiple myeloma (NDMM), the intervention is with AZD0120 ± maintenance). Module 2 consists of NDMM with AZD0120 ± maintenance.