Provided is a fusion protein comprising IL-2 protein and CD80 protein. A fusion protein comprising CD80 fragment, immunoglobulin Fc, and an IL-2 variant can activate immune cells, such as natural killer cells, and at the same time, can control immune cell regulatory activity of regulatory T cells. Therefore, a pharmaceutical composition comprising the fusion protein as an active ingredient is very industrially useful in that such pharmaceutical composition can increase immune activity in the body, and thus can be effectively used against infectious diseases as well as cancer.
