To evaluate the activation status of the NK cells in TNBC patients, we performed immunofluorescence staining for the activated lymphocyte marker CD69 and the NK cell activating receptor NKG2D, and found that NK cells from tumor tissues with higher IDO-1 expression are less activated than those from tumors expressing lower IDO-1 (Fig. 1E). Here, KLRK1 is linked to neoplasm.