Off election, on the supposed big "Russian collusion" reveal to come this week. See John Solomon last week, others (Housley) hinting something going to happen - Durham.
Pure pure pure speculation, if it's "big," who is being exposed to legal jeopardy? Rod Rosenstein for 18 USC 242, deprivation of rights under color of law for appointment of Mueller with no predicate.
Why Rosenstein? He's nominally a republican, Trump nominated and appointed him DAG. He left with well wishes from Barr, on good terms. All that means it's more difficult to advance "Trump and his toadie Barr are attacking his enemies." Compare with doing same to Weissman, and that is easy to say "Trump going after enemies."
The typical immunity to prosecutor and investigator is as to civil cases, and it makes sense there. But civil immunity is of no use in criminal court.