There were multiple attempts to make it legal for US companies to transfer and process EU data. They were all overturned in court after a few years because US s

There were multiple attempts to make it legal for US companies to transfer and process EU data. They were all overturned in court after a few years because US surveillance law is incompatible with basic rights EU citizens have. So my layman believe is that they don't need a treaty, since it will probably be overturned anyway.