A quick history of Burisma’s corruption in Ukraine shows it has nothing to do with Hunter Biden.
Investigation into Burisma began before Hunter Biden was hired:
Since 2012, the Ukrainian prosecutor general had been investigating Burisma's owner, oligarch Mykola Zlochevsky, over allegations of money laundering, tax evasion, and corruption.[65]Office of the Prosecutor General of Ukraine and National Anti-Corruption Bureau of Ukraine (NABU) have conducted in total 15 investigations on Burisma's owner Zlochevsky.[38] In 2016, former Prosecutor General Yuriy Lutsenko accused Burisma subsidiaries of conspiracy and tax evasion of about one billion hryvnias (US$70 million) in 2014–2015, but later during investigation subsidiaries of Burisma were not mentioned.[39]
While Hunter Biden was not an expert on Ukraine or the natural gas industry, he was an attorney who Burisma hired (along with his firm) to help with corporate governance best practices:
Biden's son Hunter Biden joined the board of directors of Burisma Holdings, a Ukrainian energy company, on April 18, 2014.[65][66][67] Hunter, then an attorney with Boies Schiller Flexner, was hired to help Burisma with corporate governance best practices, and a consulting firm in which Hunter is a partner was also retained by Burisma.[65][68][69]
Joe Biden’s involvement with Ukraine was in an official capacity. It represented the official, stated, policy of the United States and its allies, and the policy was not advantageous to Burisma:
The Obama administration and other governments and non-governmental organizations soon became concerned that Shokin was not adequately pursuing corruption in Ukraine, was protecting the political elite, and was regarded as "an obstacle to anti-corruption efforts".[73][74] Among other issues, he was slow-walking the investigation into Zlochevsky and Burisma, to the extent that Obama administration officials were considering launching their own criminal investigation into the company for possible money laundering.[65] Shokin has said he believes he was fired because of his Burisma investigation, where Hunter Biden was allegedly a subject; however, that investigation was dormant at the time Shokin was fired.[70][75]
Note that part of the policy that Joe Biden was pursuing for the U.S. and its allies was to REOPEN the Burisma investigation – not shut it down!
Look who attempted another quid pro quo for manufactured dirt on Biden and Ukraine:
Dmytry Firtash is a Ukrainian oligarch who is prominent in the natural gas sector. In 2017, the Justice Department characterized him as being an "upper echelon (associate) of Russian organized crime."[107] Living in Vienna, Austria, for five years he has been fighting extradition to the U.S. on bribery and racketeering charges, and has been seeking to have the charges dropped.
Firtash is represented by Trump and Giuliani associates Joseph diGenova and his wife Victoria Toensing, having hired them on Parnas's recommendation. The New York Times reported in November that Giuliani had directed Parnas to approach Firtash with the recommendation, with the proposition that Firtash could help to provide compromising information on Biden, which Parnas's attorney described was "part of any potential resolution to [Firtash's] extradition matter."[111] Shokin's statement notes that it was prepared "at the request of lawyers acting for Dmitry Firtash."[112][113]
Bloomberg News reported on October 18 that during the summer of 2019 Firtash associates began attempting to dig up dirt on the Bidens in an effort to solicit Giuliani's assistance with Firtash's legal matters, as well as hiring diGenova and Toensing in July.
The New York Times reported that weeks earlier, before his associates Parnas and Fruman were indicted, Giuliani met with officials with the criminal and fraud divisions of the Justice Department regarding what Giuliani characterized as a "very, very sensitive" foreign bribery case involving a client of his. The Times did not name whom the case involved, but shortly after publication of the story Giuliani told a reporter it was not Firtash.[115][116] Two days later, the Justice Department stated its officials would not have met with Giuliani had they known his associates were under investigation by the SDNY.[117]
diGenova has said he has known attorney general Bill Barr for thirty years, as they both worked in the Reagan/Bush Justice Department.[118] The Washington Post reported on October 22 that after they began representing Firtash, Toensing and diGenova secured a rare face-to-face meeting with Barr to argue the Firtash charges should be dropped.[119] Prior to that mid-August meeting, Barr had been briefed in detail on the initial whistleblower complaint within the CIA that had been forwarded to the Justice Department, as well as on Giuliani's activities in Ukraine. Barr declined to intervene in the Firtash case.[111]
Bloomberg News also reported that its sources told them Giuliani's high-profile publicity of the Shokin statement had greatly reduced the chances of the Justice Department dropping the charges against Firtash, as it would appear to be a political quid pro quo.[114]
Evidence that Zelenski did know about a quid pro quo before the July 25th call:
Days before Trump's July 25 call with Zelensky, Giuliani spoke on the phone with Zelensky aide Andrey Yermak [Wikidata] about a Biden investigation, as well as a prospective White House meeting between Zelensky and Trump that was sought by Ukrainian officials.[130] According to Zelensky's advisor Serhiy Leshchenko, Trump was willing to have a phone conversation with Zelensky only on the precondition that they discuss the possibility of investigating the Biden family. Leshchenko later sought to backtrack his comments, saying he did not know if officials had viewed discussing Biden as a precondition for a meeting.[131]
Text messages given to Congress by special envoy to Ukraine Kurt Volker in October suggest that Zelensky's aide Yermak was told that Zelensky would be invited for a White House visit only if he promised to carry out the requested investigations. On July 25, just before Trump's phone call, Volker texted to Yermak: "heard from White House—assuming President Z convinces trump he will investigate / 'get to the bottom of what happened' in 2016, we will nail down date for visit to Washington."[132]
Additionally, regarding knowledge of the withholding of military aid:
The administration notified Congress in February 2019 and May 2019 that it intended to release this aid to Ukraine, with the Defense Department certifying that Ukraine had made sufficient progress in fighting corruption.[172][174] Despite the notifications to Congress, in June 2019, the Trump administration placed military aid to Ukraine on hold.[175] The date of the hold was originally reported as mid-July.[172][173][176] The Washington Post reported on September 23 that at least a week before his July 25 call with Zelensky, Trump directed his acting chief of staff Mick Mulvaney to withhold[clarify] $400 million in military aid to Ukraine. This directive was conveyed by the Office of Management and Budget to the State Department and Pentagon, stating Trump had concerns about whether the money should be spent, with instructions to tell lawmakers the funds were being delayed due to an "interagency process".[172] The New York Times reported that "high-level Ukrainian officials" were aware that the Trump administration had purposely frozen the military aid by the first week of August 2019, and they were told to contact Mick Mulvaney to resolve the matter.[177]
For more details see:
https://en.wikipedia.org/wiki/Trump%E2%80%93Ukraine_scandal