The New York Times is reporting that American intelligence officials determined that the Russian government was offering bounties to Afghan militants to kill US soldiers and that Trump has known about it since March but has refused to confront Putin about it.
Given Trumps track record, when he gets asked about this, I won't be shocked if he says 'Well, I asked Putin and he says he didn't do it and I believe him'. Trump supporters will probably make excuses for it, too, even though if this had happened under Obama they would have demanded Obama be impeached and executed for it. Republicans running for election or re-election will flee from reporters when they ask about it.
Update: Russia wasn't paying the Taliban to just kill American soldiers; they were also paying them to kill UK/NATO soldiers, too.