This is false.
Numerous, almost routine communication and coordination between the Trump campaign and various individuals acting as cut outs were confirmed. The facts have not changed.
Trump skated because he had an Attorney General who covered for him. And because he employed cut outs to do the collusion, so no one in the official campaign could be accuses of collusion using the legal definition.
It had never occurred to anyone to pass a law outlawing Presidential campaigns from receiving covert support from other nations or their intelligence agencies.
The idea was unthinkable.
Until Trump thought of it.
Then the Trump regime engaged in a wholesale pattern of obstruction of justice up to and including defying Congressional subpoenas.
Mueller assembled the facts, and then turned them over to the Justice Department, then headed by Trump's "wing man", who made sure no grand jury ever saw the report. So, since no action was taken, Barr submarined the "collusion" case.