appear to be part of the feud between Giuliani and Pompeo. Pompeo is distancing himself from Giuliani's investigation - indicating that he was disinterested in Giuliani's debunked theories.
This isn't the main strand of the impeachment investigation, which is about Trump coercing Ukraine to provide help to him in the election at the expense of US foreign policy. High crime, misdemeanour, bribe, breach of oath of office, and so on. All per the memo of the transcript released by the White House.