CXCL13 and non-small cell lung carcinoma: Targeted RNA-Seq shows that the tumor microenvironment of NSCLC upregulates regulatory pathways in CD4+ T cells and exhaustion in CD8+ T cells, and analysis of a single cell RNA sequencing dataset shows that CD39+CD4+ cells are enriched in Treg signature gene-sets, and CD39+CD103+ cytotoxic T lymphocyte show gene signatures indicative of an exhausted cytotoxic phenotype with upregulated expression of CXCL13.