The PD-L1 expressions on dendritic and tumor cells are induced by exposure to IFN-γ, which is released by effector T-cells [35], and the PD-L1 expression on immune cells is associated with the extent of effector T-cell associated gene expression, including IFNG, GZMB, and CXCL9 [34], suggesting that those tumors without PD-L1 expression are in the hypoactive effector T-cell state. Here, CXCL9 is linked to neoplasm.