Although in most studies, CTLA-4 blockade monotherapy significantly delayed tumor growth or improved mouse survival, in some cancers including 4T1 breast cancer, MC38 colon cancer, B16 melanoma, lung cancer, and lymphoma, its efficacy has only been demonstrated when combined with cancer vaccines or other therapeutic modalities including monoclonal antibodies, chemotherapeutic drugs, or radiation. This evidence concerns the gene CTLA4 and lung cancer.