A drug used with other drugs to treat certain types of follicular lymphoma that have not already been treated. It is also used with bendamustine to treat follicular lymphoma that came back or has not gotten better after treatment with rituximab. Obinutuzumab is also used with chlorambucil to treat chronic lymphocytic leukemia (CLL) that has not already been treated. It is also being studied in the treatment of other types of cancer. Obinutuzumab binds to a protein called CD20, which is found on B cells (a type of white blood cell) and some types of leukemia and lymphoma cells. This may help the immune system kill cancer cells. Obinutuzumab is a type of monoclonal antibody. Also called Gazyva.