Some news at
https://www.washingtonpost.com/world...258_story.html including:
The Green Pass is a part of the European Union’s digital covid certificate program. In the news conference, neither Draghi nor Speranza made clear how the requirements would apply to tourists from non-E.U. countries. But a health ministry spokesman said that equivalent vaccination certificates, including those from the United States, would be recognized.
There's a government document on entry to Italy that includes a reproduction of the CDC card as acceptable proof of vaccination.