CD274 and squamous cell carcinoma: Given the relatively high expression rate of PD-L1 in squamous cell carcinomas, it is not surprising that NSCLCs with a squamous histology tended to have better response rates (e.g., a 6-month progression-free survival rate) in clinical trials of PD-1/PD-L1 or PD-L2-targeted immunotherapy than did those with a non-squamous histology10, 11.