My theory for end of season: Georgiou dies in a blaze of glory taking down Klingons. After her death Burnham finds out that Georgiou (with help of Sarek as a part of their deal to make her captain) filed a final statement exonerating Burnham of the mutiny (since as far as Starfleet is concerned the emperor is real Georgiou). Burnham becomes commander of the Discovery under Saruh. The Admiral goes crazy and is placed in an asylum. Final scene - Voq in mirror universe freeing prisoners in a Terran prison and PU Lorca walks out of cell. I think Ash may be key to the end of hostilities since he is human but can speak as Klingon with Klingon memories. He may be the one that can sue for peace as a bridge between the two.