We further validated that dexamethasone can also suppress the PD-L1 and IDO1 pathway in several other cancer cell lines, including thyroid cancer cell line BCPAP, pancreatic cancer cell line SW1990, lung cancer cell line NCI-H358, breast cancer cell line MDA-MB-231, and GC cell lines Hs746T and MKN7 (Fig. 3A). Here, IDO1 is linked to breast cancer.