Quid pro quo — Latin for “something for something” — is a common concept in foreign relations. U.S. assistance for other countries is typically contingent on an agreement to help achieve an American objective. The impeachment inquiry is focused on whether President Trump abused his office by seeking a quid pro quo from Ukraine that would benefit him personally rather than promote the country’s interests: namely, investigations of his political opponents.
Ukraine-U.S. Relations
Washington Post: The quid pro quo evidence so far
US President Donald Trump and Ukrainian President Volodymyr Zelensky speak during a meeting in New York on Sept. 25, 2019, on the sidelines of the United Nations General Assembly.