CD274 and neoplasm: PD-L1 expression is associated with an increased likelihood of response to PD-1 pathway blockade, but response to ICIs is also observed in patients without tumor PD-L1 expression.[52] Moreover, PD-L1 expression is heterogeneous, both within and between tumors.[53] Despite these limitations, tumor PD-L1 expression should be evaluated in all newly diagnosed patients with advanced NSCLC.