Consistently, in the 4-nitroquinoline 1-oxide-induced malignant oral/esophageal injury model, EVs carrying PD-L1 isolated from supernatants of murine or human HNSCC cell lines hampered the infiltration of CD4+ T and CD8+ T cells into the tumor microenvironment, thereby accelerating tumor progression [69]. Here, CD274 is linked to head and neck squamous cell carcinoma.