Analysing the starting lineup of Bayern Munich

The line up of Bayern Munich is impressive and can match that of Manchester City comfortably. But the notable things are;
1. Cancelo is on the reserve in his return to Etihad.
2. Mane and Muller are on the bench. I don't know.if Tuchel wants to be playing Sane over Mane and Gnabrry over Muller. That of Muller is understandable but I don't understand the reason behind that of Sadio Mane being played from the bench.