It’s pretty well known he helped launder money outside Russia for the oligarchs years and years ago, and the mueller report basically laid out serious wrong doing the first time. No one believed it because he refused to recommend prosecution or to claim he should be indicted only because he took the position it was a question for congress or for prosecutors after his term ended and to informally indict him in the report would amount to a violation of trump’s right to a speedy trial, which in retrospect is fucking laughable, but the obstruction of justice claim was spot on and there was evidence of Russian offers to help Trump’s campaign and in some instances they were receptive. There was ultimately not enough in his view to charge but mueller did not exonerate him, in fact the report on collusion is quite damning even point to the exact meeting in Trump tower NYC where it likely would have occurred, but like most mob bosses it can be extremely hard to pin exact proof on the one guy. There was so much god damn smoke and has been for decades to summarily dismiss the “special” relationship between Russia and Trump is straight denial.