CD274 and non-small cell lung carcinoma: Positive PD-L1 expression and high tumor mutation burden (TMB) were considered to predict the response to immunotherapy in NSCLC [13,14], but there is a subset of LUSC patients with PD-L1 expression <1% who benefit from ICIs, suggesting that PD-L1 IHC staining alone is not perfect enough to identify all potential immunotherapy responses in the population [6].