CD274 and neoplasm: More importantly, we highlighted several future key directions for sEV PD-L1, with particular emphasis on (a) selective purification of PD-L1-positive sEVs with natural properties and functions, (b) heterogeneity of PD-L1-positive sEVs, (c) standardization of sEV PD-L1-based liquid biopsy, and (d) novel tumor therapies based on sEV PD-L1.