To those who may be confused by those saying that collusion is not a crime: Two or more dieters colluding to sneak out to the ice cream parlor does not constitute a crime; two or more yeggs colluding to crack some safes are.
Collusion is a synonym for conspiracy, which most people think is illegal but which, like collusion, requires a criminal act to describe, before becoming a felony. It has to be a conspiracy to commit a crime before it is actionable.
So when Trump tells you there was no collusion, he is wrong, as usual. There is no doubt that there was collusion; what remains to be determined is whether it was also a crime.