The efficacy of these CIs, especially PD-(L)1 mAb, often depends on and correlates with PD-L1 expression in the TME, mutational burden, and the number of tumor-infiltrating lymphocytes (TILs).13, 84, 85, 86, 87 High ORRs of 57% are reported in immunogenic cancers such as melanoma, which is ascribed to a high mutational burden and high numbers of TILs.88, 89 In tumors with lower mutational burden (e.g., mesothelioma), ORRs remain between 9% and 25%,90 likely due to the relative low frequency of TILs. The gene discussed is CD274; the disease is mesothelioma.