CTLA4 and melanoma: Furthermore, a simultaneous combination treatment of anti‐PD‐1 and anti‐CTLA‐4 with STING‐agonist‐containing liposomes effectively reduced the number of pulmonary metastatic nodules in a mouse melanoma lung metastasis model, whereas free cGAMP + anti‐PD‐1 + anti‐CTLA‐4 did not.420