CD274 and non-small cell lung carcinoma: The study by Hong et al. [29] observed a higher expression of PD-L1 in squamous cell carcinomas than adenocarcinomas, while the study recently published by Zheng and colleagues [31] found a higher positivity of PD-L1 in squamous cell carcinomas and other histological subtypes of NSCLC compared to adenocarcinomas.