Dostarlimab : A New hope for treatment of colorectal cancer and endometrial cancer: Immunotherapy is one of the major strategies for cancer treatment. Immunotherapy, also known as biological therapy, uses your body's immune system to fight cancer. Cancer can survive unchecked in your body because your immune system doesn't recognize it as an intruder. Immunotherapy can help your immune system "see" the cancer and attack it.Monoclonal antibody is an antibody produced by a single clone of cells or cell line and consisting of identical antibody molecules. A monoclonal antibody is an antibody made by cloning a unique white blood cell.