The FBI will merely state that because this is an ongoing investigation, there will be no disclosure and no further comment.
And that is exactly what the DemonRats want and need. Cummings is playing his assigned role perfectly.
Long ago in NJ a top mafia guy on trial and his attorney made a motion for the fbi to release any illegally obtained eavesdropping materials they had. The expectation was they could not admit having any. They released them in total. Moral of story: never ask question if you cannot live with consequences. Guy was convicted on all counts I believe.