PD-L1 assessment in cytology samples predicts treatment response to checkpoint inhibitors in NSCLC

•In a large population, cytology and histology samples had similar PD-L1 TPS distribution.•Despite different sites of sampling, overall PD-L1 TPS proportions remained similar.•PD-L1 TPS determined by the 22C3 assay on cytology was predictive of treatment response.•PFS to PD1 inhibitors were similar according to PD-L1 TPS on cytology vs histology samples.•PFS of patients with PD-L1 ≥ 50 % on cytology was comparable to clinical trials.