CD274 and cancer: Previous preclinical studies in other cancers including hepatocellular carcinoma (30), pancreatic ductal adenocarcinoma (16), head and neck squamous cell carcinoma (18), and non-small cell lung cancer (18, 31) have found that combining anti-PD-1 or anti-PD-L1 therapies with RT improve treatment response by circumventing this adaptive upregulation of PD-L1; such combinations may likewise be assessed in our mesothelioma models.