There is this problem in multiple countries I believe. From what I understand, the US asks you to report what you earn outside of the US but also what you paid

There is this problem in multiple countries I believe. From what I understand, the US asks you to report what you earn outside of the US but also what you paid as taxes. If the foreign country has a tax treaty with the US you would only pay the difference (in case the US taxes are higher than the foreign).