CD274 and lung carcinoma: KRAS-mutant NSCLC is the target of interest for PD-1/PD-L1 inhibition for the following reasons: KRAS-mutant lung cancers are typically smoking-associated tumors, and are therefore often associated with a high mutational burden [47,48]; these cancers frequently show abundant T-cell infiltration; PD-L1 expression is present in approximately 24–55% of KRAS-mutant lung adenocarcinomas [49,50].