CD274 and neoplasm: Higher PD-L1 tumor proportion scores (TPS) as well as expression of other markers such as PD-1, presence of tumor-infiltrating lymphocytes (TILs) or combinations of immunohistochemical staining such as PD-L1 in combination with CD8 + T cells represent surrogate markers of an immune-active or “hot” tumor immune microenvironment (TME) and correlate with objective response rates of tumors treated with antibodies directed against the PD-L1/PD-1 axis [15–17].