It isn't just her, there are lots of people involved, including congress-people and senators. I truely think Biden/Kerry/Hillary/Obama/Schiff/Bolton/Brennen/Pelosi/Romney. Even the whistleblower , who speeks fluent Russian/Ukrainian. This goes back to the tragic coup in Ukraine, in which 100 people(40 police) were killed by snipers to trigger the coup. And it's why you now see the likes of Biden, Kerry and Pelosi have children that 'work', by that I mean have paid directorships, in Ukrainian energy companies. THAT is why they are so nervous about Trump going after corruption in Ukraine - because all those names, and more, are guilty of corruption.
Trump took over from Obama, there are still lots of Obama's people still in places they can do damage to Trump. They have been after Trump since before he took office, because they though hillary would win and they didn't cover their tracks, so to stop Trump investigating they have been throwing everything they can at Trump, Russian meddling and now the impeachment failure, it all takes up valuable time that Trump could have been using to investigate THEM.
There is a lot more to it, but that will get you going.