It appears that the big issue is that the Obama appointed ambassador to Ukraine was refusing to do her job and was blocking Ukraine officials from entering the US (2018) to discuss this matter--the Biden investigation--with US officials.
Paul Mirengoff, citing Never Trump and one week presidential candidate David French, finds something improper about Trump's personal lawyer, Giuliani, getting involved, supposedly at the request of the State Dept:
However, John Solomon--who has spoken with persons who were personally involved--says that Giuliani's involvement was more complicated than people like David French think.
The Ambassador to Ukraine was yanked ahead of schedule (5/2019), apparently after stepping in in a big way in the Ukraine elections--demanding that the Ukraine anti-corruption prosecutor be fired.
So it seems that normal State Dept. functioning wasn't happening, due to Obama holdovers, and that may explain Ukraine reaching out to people who could communicate with the US government for them, since normal channels were being blocked.
ADDENDUM: This illustrates that ever since the US sponsored coup in Ukraine (2014) our relations with that country have been anything but normal, beginning with the Obama/Clinton use of Ukraine to try to smear Trump. The abnormal relations continued after the election with the Obama appointed ambassador's very unusual--even very suspicious--actitivies.
The bottom line appears to be that Trump will emerge pretty much unscathed, but that Biden won't. And that once again we have received confirmation that Ukraine is at the center of the Russia Hoax.
UPDATE: Not so much an update as an addendum. Don Surber let's loose in enjoyable fashion: Democrats have impeached themselves. Here's how he starts off--but he keeps going:
The Democrat Party began the week by demanding the impeachment of Justice Brett Kavanaugh over an incident 30 years ago that the alleged victim does not recall. The Democrat Party ended the week by demanding the impeachment of President Donald John Trump because he may have said something to a foreign leader that was heard third-hand by a "whistle blower."
In 1972, Democrats lost the presidency in a 49-state landslide because they called for taxing everything.
They still do, but now they also want to impeach everyone and anyone who disagrees with them. The Queen of Hearts in Alice's Adventures in Wonderland shouted "Off With His Head" about someone every minute or so. She would be part of the Democrat Party's moderate wing today.