Joe Biden is addressing the full context of the claim that he got Viktor Shokin fired to protect Burisma and Hunter Biden from investigation by Shokin. The $3.5 million is a new claim recently tacked on. Joe Biden is referring to the World Bank's support for reforms in Ukraine.
MSN provides some important context.
The president accused Joe Biden of trying to have the Ukrainian prosecutor general ousted when he was vice president in order to shut down an investigation into Burisma and protect Hunter Biden. Trump also alleged that Hunter Biden received "$3.5 million from Moscow."
I'll address that $3.5 million in a moment. MSN goes on to point out that...
It is true that Biden, when he was vice president, pushed hard for the Ukrainian government to fire Viktor Shokin, the prosecutor general at the time. However, Biden was acting in his official capacity as part of the Obama administration when pushing for Shokin's firing because the prosecutor did not make a concerted effort to fight corruption. The US's western allies and institutions, including the World Bank, supported the move.
Presumably what Joe Biden was trying to refute the entire claim that he got Viktor Shokin fired to protect Burisma and Hunter from investigation. In reality, many institutions including the World Bank, supported the need for reform in Ukraine. The investigation into Bursma did not cover the period when Hunter Biden was on its board.
“Changes to the board of Burisma Limited, which are currently the object of international attention, took place only in May 2014, and therefore are not and never were the subject of (the anti-corruption bureau’s) investigation,” the National Anti-Corruption Bureau of Ukraine’s statement said.
The Hill reported October 2019...
Shokin was so widely reviled that the International Monetary Fund, the World Bank, the European Union, the Ukraine Anti-Corruption Action Center and the chairman of the Ukraine parliamentary anticorruption committee, among others, also sought his removal.
I can't find a direct reference to the World Bank's support, but here is a report from The Guardian from Feb 2016 when the Ukraine corruption campaign was ongoing: [International Monetary Fund] warns Ukraine it will halt $40bn bailout unless corruption stops. I would not expect to find the World Bank, EU, nor IMF making any statements regarding Hunter Biden now; the facts of the Ukraine anti-corruption campaign are clear. This is tempest solely in America's teapot.
The $3.5 million comes from a Republican Senate Report on Hunter Biden released in September 2020. One of its claims is that...
…On Feb. 14, 2014, Baturina wired $3.5 million to a Rosemont Seneca Thornton LLC (Rosemont Seneca Thornton) bank account for a “Consultancy Agreement DD12.02.2014.” Rosemont Seneca Thornton is an investment firm co-founded by Hunter Biden that was incorporated on May 28, 2013 in Wilmington, Del.
Elena Baturina is the former wife of the late Yuri Luzhkov, who was the mayor of Moscow and was fired in 2010 by then-Russian president Dmitry Medvedev over corruption allegations. The Senate report gives no context for the payment, nor any implication that it was illegal, nor whether Biden received any of that money.
Hunter Biden's attorney refutes this claim, stating Hunter Biden was not involved with Rosemont Seneca Thorton.
The Senate report falsely alleges that Hunter Biden had a financial relationship with Russian businesswoman Yelena Baturina and that he received $3.5 million from Baturina. Hunter Biden was not a co-founder of Rosemont Seneca Thornton LLC (“RST”) nor did he have an equity interest in RST, so the claim that he was paid $3.5 million is false.
The Democratic Minority Report says the information is unverified and not independently confirmed.
The information in the documents cited by the Republicans has not been verified, and we are not aware of any other Congressional committee ever releasing this sort of information in this manner.
The Chairmen spent a year investigating Russian-backed allegations of wrongdoing by Vice President Biden in Ukraine, only to find the allegations discredited by their own investigation. Here the Republicans made no attempt to independently investigate the transactions at issue, perhaps to avoid the embarrassment of seeing these allegations discredited as well.