This is a multi-center, open-label, phase II study of Durvalumab in combination with Lenalidomide for treatment of relapsed/refractory EBV associated DLBCL subtypes, primary testicular lymphoma and primary CNS lymphoma using a Simon's Two-stage Minimax design. Simon's two-stage Minimax design will be used to investigate if the overall response rate (ORR) is at least 45% against a no-interest ORR of 20%.