However, PD-L1 is widely inducible on immune subsets, tumor cells, and even endothelial cells, in an IFN-γ-dependent process.27 Thus, both tumor and host PD-L1 are intimately involved in checkpoint blockade.28 In some malignancies such as colon cancer, tumor immune infiltrates express PD-L1 at significantly greater levels than tumor cells.29 Thus, it is essential to study the role of tumor extrinsic PD-L1. The gene discussed is IFNG; the disease is neoplasm.