CD274 and lung adenocarcinoma: In contrast to lung adenocarcinoma with an “epithelial” phenotype, it constitutes endogenous immune activation, such as elevated levels of the immune co-stimulatory molecules (i.e., IFN-γand CXCL10), along with the simultaneous elevation of multiple immune checkpoint molecules (e.g., elevated PD-1 and PD-L1) [89].