EDNRA and neoplasm: In a previous study, we reported that sulfisoxazole (SFX) suppresses tumor growth and metastasis by inhibiting EXO secretion by targeting endothelin receptor A (ETA).[10] This finding implied that the inhibition of tumor‐derived EXOs by SFX has the potential to suppress immune evasion by tumor‐derived exosomal PD‐L1.