the mueller report
Special Counsel Robert Mueller's team was never actually looking for evidence of "collusion" but rather conspiracy, his redacted report says.
Mueller's report states that the investigation set out to find whether members of President Trump's campaign conspired with Russia in its election interference and did not establish that they did so. But while Trump has chalked this up to Mueller finding "no collusion," Mueller's report notes that collusion is "not a specific offense or theory of liability found in the U.S. code" and is not a term in federal criminal law.
Therefore, the investigation was always working with the criminal definition of conspiracy "as defined in federal law, not the commonly discussed term 'collusion.'" Mueller was specifically looking for coordination, i.e. "an agreement — tacit or express — between the Trump campaign and the Russian government on election interference," which would require both parties to act in a way that was "informed by or responsive to the other’s actions or interests," per The Washington Post.
Ultimately, while the investigation doesn't establish that Trump's campaign illegally conspired with Russia, it says the campaign expected to benefit from Russia's election interference.