CD274 and non-small cell lung carcinoma: Detecting the expression of PD-L1 by immunohistochemistry has been approved as a companion diagnostic test for the use of pembrolizumab in non-small-cell lung cancer (NSCLC), gastric/gastroesophageal junction adenocarcinoma, cervical cancer (CC), and urothelial cancer by the Food and Drug Administration (FDA) [80–84].