The complaint alleges that Volker went to Kiev in late July and met with Ukrainian President Volodymyr Zelensky and other Ukrainian political figures and “reportedly provided advice to the Ukrainian leadership about how to ‘navigate’ the demands that the President had made of Mr. Zelenskyy.”

…[Trump] asked Zelensky to “investigate” former Vice President Joe Biden and his son, Hunter Biden, who sat on the board of a Ukrainian natural gas company.

Whistleblower complaint: U.S. special envoy to Ukraine steps down a day after whistleblower complaint was released – CBS News

hmmmm