CD274 and head and neck squamous cell carcinoma: Furthermore, PD-L1-EVs from head and neck squamous cell carcinoma cells suppress B-cell proliferation and activity and increase PD-1 and LAG3 expression on their surface; PD-L1-EVs from gastric cancer cells promote myeloid-derived suppressor cell expansion and differentiation, suggesting that a wide range of immune cells can be affected by PD-L1-EVs83,84.