 This is a single-arm, multicenter, Phase 2 study to evaluate the efficacy and safety of the combination regimen of daratumumab plus durvalumab D2. The study will consist of 2 parts; Part 1 has a 2-stage design while Part 2 consists of an expansion phase. Subjects will receive intravenous IV DARA at 16 mgkg on the same dosing schedule weekly QW, every 2 weeks Q2W or every 4 weeks Q4W of each 28-day cycle received on their last prior therapy containing DARA. The dosing schedule for DARA may be adjusted during the course of the study as outlined in the protocol. Subjects will also receive IV DURVA at 1500 mg on Day 2 Cycle 1 and on Day 1 Cycles 2 of each 28-day treatment cycle. 