CD4 and non-small cell lung carcinoma: In NSCLC patients, we find an increase of CD39+ cells in NCL tissue compared with levels in peripheral blood, which was further elevated in the tumor microenvironment (TME) of NSCLC among CD4+ and CD8+ T cells, in line with published reports of multiple human solid tumors.8 13–17 We additionally observed an upregulation of CD39 expression on NK cells and fibroblasts, identified as CD90+ cells in tumor compared with NCL tissue.