The Biden administration is moving towards lifting a de facto ban on American military contractors deploying to Ukraine, four US officials familiar with the matter told CNN, to help the country’s military maintain and repair US-provided weapons systems.
https://www.businessinsider.com/ukraines-international-legion-is-still-fighting-but-not-many-left-2024-5
https://www.businessinsider.com/they-went-to-ukraine-to-be-war-heroes-and-fight-russians-2022-4