SCLCs were found to have relatively colder immune profiles than lung adenocarcinomas and squamous cell carcinomas, characterized by lower expression of <i>HLA</i> genes, immune cell, and immune checkpoint genes, except the <i>LAG3</i> gene.<h4>Conclusions</h4>Clinical-grade SCLC RNA expression profiling has value for SCLC subtyping, design of clinical trials, and identification of patients for trials and potential targeted therapy. This evidence concerns the gene LAG3 and squamous cell carcinoma.