This is a randomised, multicentre, controlled, open-label, Phase III global study comparing the efficacy and safety of AZD0120 versus standard regimens (DKd \[daratumumab, carfilzomib, and dexamethasone\], DPd \[daratumumab, pomalidomide, and dexamethasone\], PVd \[pomalidomide, bortezomib and dexamethasone\], or Kd \[carfilzomib and dexamethasone\]) in participants with RRMM.