The emails I've linked above are part of a chain describing an alleged trove of incriminating dirt on HRC collected by a Russian prosecutor that Donald Trump Jr. was very interested in. That trove either did not exist, or at least was not actually provided to the Trump campaign. So these communications "didn't go anywhere," but it sure showed interest on Donny Jr.'s part!
Collusion? Merely "attempted collusion"? No big deal at all? Something all presidential campaigns should willingly do in the future?
You be the judge. Thanks to Mueller team's work, now we the people know.
Quoting from p. 5 of Mueller's Executive summary:
"The social media campaign and the GRU hacking operations coincided with a series of contacts between Trump Campaign officials and individuals with ties to the Russian government. The Office investigated whether those contacts reflected or resulted in the Campaign conspiring or coordinating with Russia in its election-interference activities. Although the investigation established that the Russian government perceived it would benefit from a Trump presidency and worked to secure that outcome, and that the Campaign expected it would benefit electorally from information stolen and released through Russian efforts, the investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."
https://www.snopes.com/uploads/2019/05/Mueller-Summary-Vol-1.pdf
So, the Mueller team elected not to characterize these emails as "conspiring" or "coordinating" with Russia on the Trump campaign's part. I think reasonable minds can differ on that.
However, it may surprise you to learn that Mueller probe was not set up to investigate or "take down" Trump or his campaign specifically: but rather to unearth any and all evidence of systematic Russian interference in the '16 election.
And it found boatloads of it. Therefore, the Mueller investigation was not a hoax or a failure in the slightest.