RecruitingPhase 3Drug trialMosunetuzumab-Lenalidomide Versus Investigator Choices in Patients With Relapsed or Refractory Marginal Zone LymphomaThis is an open label, multi-center, international, randomized phase III trial to compare the efficacy of Mosunetuzumab-Lenalidomide with investigator choices exclusively in R/R MZL patients. Patients with a proven diagnosis of EMZL, SMZL or NMZL subtypes and previously treated with at least one prior systemic treatment and not more than three prior lines are eligible. Previous treatment line must include at least one systemic line with a drug targeting CD20 (monoclonal antibody at least 2 cycles) with or without chemotherapy (R-CHOP, R-Bendamustine, R-CVP, R-Chlorambucil at least 2 cycles) or targeted treatment such as Ibrutinib. The patients will be Randomized as follows: Arm A - Experimental arm: • Mosunetuzumab-Lenalidomide Arm B - Comparator arms ( Investigator Choices): * Rituximab-Lenalidomide * Rituximab-Bendamustine * Rituximab-CHOP