CD274 and non-small cell lung carcinoma: However, ICIs showed the most benefits in NSCLC patients with a high expression level of the programmed cell death ligand-1 (PD-L1).[3] Therefore, pembrolizumab, one of the ICIs inhibiting PD-L1, was recommended in NSCLC patients with a PD-L1 expression >50%.[4] Whether patients with a low PD-L1 expression level or PD-L1 negative could benefit from pembrolizumab monotherapy is still in question, and whose treatment is a clinical challenge.