Next, we employed the CT26 pulmonary metastasis model not only to determine the extent to which the anti-metastatic property of IL-15SA/IL-15RαSu-Fc could be applied to a different tumor type, but also to combine IL-15SA/IL-15RαSu-Fc with an immune checkpoint therapy using, for example, anti-CTLA-4 or anti-PD-L1 antibodies. The gene discussed is CTLA4; the disease is neoplasm.