The Cloud Act was passed back in 2018. It was snuck onto another bill.

It was passed at a time when the Supreme Court was about to rule on whether the previous law covered warrants over data stored in foreign countries.

This involved a search involving Microsoft which ran afoul of Ireland's data localization law.

In theory, the Cloud Act gives discretion to the U.S. Gov over whether they want to add a particular country to the list of countries they can tap.

Without the Cloud Act, there is a treaty which is used by countries to request information. It has a far higher level of scrutiny, and the recipient country has to issue their own warrant.