CD274 and non-small cell lung carcinoma: Interestingly, a recent randomized, multicohort study (KEYNOTE-021) demonstrated that combination of pembrolizumab, carboplatin, and pemetrexed could be an effective and tolerable first-line treatment option for patients with advanced NSCLC [23], suggesting there might be correlation of PD-L1 expression and pemetrexed-based chemotherapy.