https://www.nytimes.com/2019/05/29/us/politics/mueller-special-counsel.html?action=click&module=Top Stories&pgtype=Homepage
What will he say? It's crazy how radicalized Trump fanatics are that they've taken the demonstrable lies of Trump and his lackey Barr as gospel. If you read the report, it documents multiple contacts between his campaign and Russia, the campaign knowing about the hacks and upcoming email releases before they happened, talking to contacts they knew represented the Russian government/intelligence agencies for Clinton information. Which did not amount to criminal conspiracy, but is kosher I guess?
The criminality was in the multiple counts of obstruction of justice by Trump that Mueller couldn't indict on because of the opinion that the President is immune from prosecution while in office.
Will Mueller correct the record on Barr's and Trump's lies? Not that it will matter to the fanatics, they'll pivot to the new talking points attacking Mueller and continue to live in fantasy land.