SCLC is strongly associated with smoking and therefore has a relatively high tumor mutation burden (TMB), suggesting that it might be responsive to immune checkpoint inhibitors (ICIs).9, 10, 11, 12 Nevertheless, only approximately 20% of SCLC tumors have a tumor proportion score for PD-L1 of more than or equal to 1%.13, 14, 15, 16 A better understanding of the transcriptomic and genomic features of SCLC is therefore needed to inform the development of optimal therapeutic strategies. This evidence concerns the gene CD274 and small cell lung carcinoma.