It is known that former smoking predicts more favourable outcomes to PD-1 blockade in non-small-cell lung cancer, which may relate to higher TMB and a tobacco gene signature,26,27 but this may not be the case for other tumour types where smoking may intensify comorbid health risks, and an ultraviolet (UV) gene signature may be more influential. This evidence concerns the gene PDCD1 and neoplasm.