I think it is fairy unlikely anything related to the Russian interference with the election will affect Trump directly, either in office or as a private citizen afterward, legally speaking. The exception would be if there are actual phone/email records that prove without doubt state of mind/intent of Trump planning on direct aid of some sort to Russia in trying to influence the election. Like a payoff etc.
On the other hand, obstruction of justice could nail him. Or, if he ever allows himself to be interviewed under oath (which I doubt his lawyers will allow), perjury.
He also might become prosecute-able under various laws for laundering money for Russians; or for campaign finance violations, etc.
However, I doubt any of these will result in him being indicted while in office, though he could certainly be in legal jeopardy afterward. The exception would be the unlikely event that the Dems take both houses of Congress in November. However, even then I doubt he will be impeached, let alone be kicked out of office. And if Dems pursue impeachment in the House, with no chance of it going anywhere, I think they will actually drive UP Trump's popularity and the GOP vote in the next presidential election. Hell, the GOP is already running on this very idea to try to increase their voter turnout for the midterms!
Personally, I think the Dems should NOT pursue impeachment, even if they hold the House.
Trump will also pardon any of his family/close associates that get nailed in this investigation, but they at least might be gettable under state law.
I doubt Trump will resign, either.
Basically, we need to boot him ourselves, as voters. And hopefully any lawmakers that won't stand up to him. Americans did this moronic shit to ourselves, and we are now suffering the consequences. ELECTIONS HAVE CONSEQUENCES. Hopefully we'll finally learn that politics is not a reality show, but I doubt it.