It's not against any law for a US President to ask a favor from a leader of another country. It was all a Communist lie.
Impeachment is for high crimes, misdemeanors and treason. Asking another leader to look into something doesn't fit any of those categories.
Let me tell you what this really was about: The commies found out that Trump asked Zelenskyy to look into the very suspicious Hunter deal. They knew they had to shut up Zelenskyy before he said anything, so they created this phony impeachment thing. They based their claim from their holy Bible, the book 1984. But the truth of the matter is there is no such thing as thought police.
They knew Zelenskyy didn't want to get in the middle of a pissing contest between Congress and the President because his country gets their money from, both places, so he didn't tell Trump anything.