The Dossier specifically alleges that the Trump Campaign was on collusion with the Russians. There's no evidence of that, but more details of events in the Dossier are being shown to be true as time goes on. If the Dossier is correct, Trump has committed what I imagine to be the most egregious crime in US Political history.
I think clarification of the meaning of the word "evidence" is in order here. Not trying to pick on you, but James Clapper said the same exact thing in an interview last week, that he had seen "no evidence" of collusion, a statement immediately seized upon and reported with glee by the conservative media. The definition you're applying seems to be similar to how Clapper used the word. It's an overly narrow definition. It equates "evidence" with what we'd call "direct" or "prima facie" evidence. By that definition, it's true. There is no audio tape of a conversation where people are colluding, and no one who is a party to any communications has admitted to collusion. However, there is a load of
circumstantial evidence here which suggests collusion. Trump says nice things about Putin - a unprecedented political stance for an American presidential candidate; Russia hacks democratic organizations to help Trump get elected; Trump changes the party platform to favor Russia; Trump publicly calls for Russia to hack Cltnton; all sorts of unexplained communications between the Trump campaign and Russian officials during the election cycle; an observed lack of candor about these communications on the part of Trump and his people. All these circumstances
suggest collusion.
I should also mention that in addition to all the circumstantial evidence, that the dossier itself is prima facie evidence, with the important caveat that the
credibility of this evidence has not yet been established.
All this is nowhere near enough to convict anyone of anything beyond a reasonable doubt in a criminal court. But that's not the same thing as saying "there is no evidence." I think that's a misleading way to characterize the current state of affairs. A better way to look at it is, there isn't
sufficient evidence right now. More is needed.