Preclinically, Sunitinib shows a synergistic antitumor effect with cytotoxic T‐lymphocyte‐associated protein 4 (CTLA‐4) monoclonal antibody (mAb) in melanoma and nonsmall cell lung cancer (NSCLC) immune competent mice by promoting the tumor‐infiltrating lymphocytes activity. The gene discussed is CTLA4; the disease is lung cancer.