Burisma put Hunter Biden on its board of directors and paid the Biden family millions of dollars for "the Biden brand" - i.e., having a sitting U.S. Vice President in its back pocket.
Sitting U.S. Vice President Joe Biden actively participated, via speakerphone, in over 20 Burisma business meetings with Mykola Zlochevsky (the owner of Burisma), Vadym Pozharski (an executive of Burisma), and his son, Hunter Biden.
Ukrainian prosecutor, Viktor Shokin, started investigating Burisma for corruption. So, Zlochevsky and Pozharski put direct pressure on the U.S. political muscle (i.e., the sitting U.S. Vice President who was now bought and paid for) in their back pocket to squash Shokin's investigation of Burisma. Bear in mind, they wanted a U.S. Vice President to squash an investigation of a Ukrainian company by a Ukrainian law enforcement official. Biden had NO lawful authority to do this, WHATSOEVER. But yet, the sitting U.S. Vice President did do as he was told and got Shokin fired.
Here is video where Joe Biden, himself, brags about using the threat of withholding U.S. funding from Ukraine to get Shokin fired ... "I'm leaving in six hours. If the prosecutor is not fired, you're not getting the money. Well, son of a bitch ... he got fired." ~ U.S. Vice President Joe Biden