"Possible collusion" refers to a situation where two or more people or entities secretly work together to cheat, deceive, or manipulate a particular outcome or situation for their own benefit. Full definition
Comey testified that the FBI investigation into possible collusion between Russia and the Trump campaign did not extend to Trump himself during the time Comey was leading the FBI. (fortune.com)
Earlier in the day, it was announced that Ty Cobb, the White House lawyer handling the investigation into possible collusion between Trump's campaign and Russia, would be replaced by Emmet Flood, a veteran Washington attorney who was part of the team representing former President Bill Clinton during his impeachment proceedings. (bloomberg.com)
The revelation of the investigation of possible collusion with Russians, and the first public confirmation of the wider probe that began last summer, came in a remarkable hearing by one branch of government examining serious allegations against another branch and the new president's election campaign. (fortune.com)