Based on the functions of the cytokine, the IL-10 family can be separated into three subfamily groups. IL-10 subfamily cytokine selects the innate and adaptive immune response and can prevent the function to reduce tissue damage. The IL-20 subfamily of cytokine works on tissues in the stroma and epithelial cells to bring out the mechanism of innate defense that manages the attack of extracellular pathogens. The IL-28 subfamily of cytokine are type III interferon (IFN) family. This subfamily share intersecting biology and signaling pathways with type I IFN family cytokines but the difference is that the type III INF family cytokines prefer to target the tissues of the epithelial cell.