They've all been incriminating themselves like treason was going out of style.
And No Such Agency has every bit of it safely tucked away.
Nunes may make his move tomorrow, reveal the FBI mole that was inserted into the Trump Campaign in 2016 (or earlier) and put Sessions (and POTUS) neatly in the "who me" role, since with evidence like he's going to lay out on the national table, even Voldemort would have to take action. It has to look obnoxiously illegal, it has to leave Sessions and Trump with clean hands, and it really has to minimize any chance of civil unrest.
My $20 bet is on the moderately-possible chance that the IG report drops tomorrow. Doubtful that it would be released in full and unredacted, but it's fun to think about. Maybe the IG Report, in whatever form we eventually end up seeing it, plays a big part in crafting the scenario above.
My $5 dollar bet on the long shot horse is the IRS, which has been quiet as a tomb for months now. There are enough tax/mail/wire fraud charges to lock up dozens of people for decades, and that's not even including the RICO possibilities. The wild card is the new IRS Commissioner, who's been practically invisible. They could pop out of nowhere and surprise everybody.