Immune checkpoint inhibitors (ICIs) are now a cornerstone of advanced non-small cell lung cancer (NSCLC) treatment. However, heterogeneity in ICI benefit is significant, and it is increasingly apparent that resistance is likely multifactorial. As cigarette smoking is associated with increased tumour mutation burden (TMB) [1,2], it is possible that ‘never smokers’ could obtain less ICI benefit. Recent study-level meta-analyses report that never smokers may obtain less effect from ICIs than previous/current smokers [3,4], while small cohort studies report prognosis may be poorer in never smokers compared to previous/current smokers [1,2]. However, these studies (1) used small cohorts, (2) failed to recognise previous and current smokers have different TMBs, and (3) have not reported according to PDL1 expression.
- Non-small cell lung cancer