CD274 and cancer: Thus, PD-L1 protein detection by immunohistochemical examination of tumor specimens and evaluation of the PD-L1 tumor proportion score (TPS), which measures the percentage of marker-expressing cancer cells, are widely used as a predictive biomarker assay for anti-PD-1/PD-L1 therapies for NSCLC patients in routine clinical practice [17,19,20].