To elucidate whether combining an RARγ agonist with checkpoint blockage can overcome the relative anti-PDL-1 resistance of murine 344SQ lung cancer cells20 that were implanted subcutaneously into syngeneic mice, palpable tumors were treated with IRX4647 as a single agent or in combination with anti-PD-L1 antibody, as in Fig. 4a. Here, CD274 is linked to lung cancer.