RecruitingPhase 2ProcedureLow Dose Mosunetuzumab for the Treatment of Patients With Indolent B-Cell LymphomaThis phase II trial tests the safety, side effects and effectiveness of mosunetuzumab in treating patients with slow growing (indolent) B-cell lymphoma. Mosunetuzumab is a monoclonal antibody that may interfere with the ability of tumor cells to grow and spread.