To further investigate the cytotoxicity and cytokine secretion of CD38+ CD8+ T cells and CD38− CD8+ T cells in natural condition, we cultured single cell suspensions from peripheral blood (n = 6), adjacent normal lung tissues (n = 8) and tumor (n = 8) of NSCLC patients without TCR agonist in vitro and detected the secretion of cytotoxic molecules and cytokines through flow cytometry (Fig. 2a, b). Here, CD38 is linked to neoplasm.