Why John Stones and Aymeric Laporte are missing for Manchester City against RB Leipzig

Why John Stones and Aymeric Laporte are missing for Manchester City against RB Leipzig in their opening Champions League tie.

Why John Stones and Aymeric Laporte are missing for Manchester City against RB Leipzig
Why John Stones and Aymeric Laporte are missing for Manchester City against RB Leipzig in their opening Champions League tie.