The "Durham Report" will have as much credibility as the "Drudge Report" does these days.
A "Report" allows the D.C. criminals to cover for each other. What is often more important than what is written is how it is written, and what is censored (called "redacted"). And every guilty party, from the "Intelligence Community" to the guilty rats in the FBI, will have a shot at "redactions."
Once the "Report" is released, they can give meaningless talk to "possible indictments", but when the news cycle of their "Report" goes stale (and it will, very quickly), they can release a Friday afternoon press release that says "no criminal intent" or "does not rise to the level of" - and let everyone off the hook.
How do we know this?
Because these people have done this in the past - again, and again.
My guess is that a few underlings will be charged, but even that is a stretch. Brennan and maybe Comey will be chastised in the "Report" for doing "irregular" things - but they will not be held criminally liable for their criminality and treason.