In non-small-cell lung cancers, Deng et al. showed that current/ever smokers had higher PDCD1 and CTLA-4 expression in tumor tissues, compared with never smokers (PDCD1 median 142 vs. 36, p < 0.01; CTLA-4 median 152 vs. 59, p < 0.01) [37]. Here, PDCD1 is linked to neoplasm.