We constructed Treg differentiation model in vitro, and revealed extraordinary cooperation between melanoma cells and Tregs (Fig. 6 and Additional file 2: Fig. S9); that is, AIL inhibited PD-L1 secretion by targeting c-Jun in melanoma cells to suppress Treg differentiation, thus creating a highly efficient AIL-c-Jun-PD-L1-Treg antitumor pathway (Fig. 7). The gene discussed is CD274; the disease is melanoma.