Schiff is desperate to get any document he can to create an investigation. He must have been identified as a target of Barr Durham and has sat out any investigation related to them. If he is a target then calling for an investigation is obstruction of justice.
This is all he has left to do.
Few clips full article here
https://www.politico.com/news/2020/08/26/adam-schiff-fbi-trump-foreign-financial-ties-402318