KLRB1 and non-small cell lung carcinoma: In addition to CD8+ T cells, recent studies demonstrated the depletion of natural killer cells139 and increased emergence of Tregs at the primary tumor site compared to at the normal site.128,137,140 Tregs persist in tumors and metastasis sites to suppress antitumor immunity in NSCLC.140 Wu et al. first reported a rare T cell cluster, Th17, in NSCLC with a high expression level of KLRB1 and observed a transitional phenotype from naïve cells to Tregs.141