The Mueller report concluded that there was no evidence the President and his team colluded with Russians to influence the election. But, they also concluded the Russians successfully influenced the election through social media and facilitating the hacking, modification and release of emails. That middle word gets overlooked, but per Thomas Rid (a cybersecurity expert at Johns Hopkins University who has closely studied Russian operations) in an interview on PBS Newshour, the Russian agents would modify things they leaked.
Further, per an article in MSN.com, entitled “Mueller report shows Trump campaign left itself wide open to Russians, officials say,” the Trump campaign naively opened themselves for being used. Here is a quote from the article which can be linked below.
“The Russians came up against a group of people who were not intelligence savvy and who were predisposed not to listen to the intelligence and counterintelligence community,” said Luis Rueda, who spent 27 years as a CIA operations officer. “The Russians made a very bold and aggressive attempt to take advantage of that — to try to compromise people, to try to leverage their access.”
More will come from the pending court cases, but this article notes the Mueller report paints a very unflattering picture of the Trump campaign and White House. I personally believe there was collusion, as they did not interview the President and they also did not dive as deep as they could have. To me, there was too much story changing going on, especially about financial ties to Russia, for there not to be some nefarious effort going on.
Setting that aside, even if there was no collusion, the Russians were invited in to play and they would not do this unless they had something to gain. I encourage you to read the attached brief article. Or, check out the PBS Newshour interview because the Russians will not go away in 2020.