Lifting faces in a backlit photo

A backlit photo has two problems at once: the faces are in the shadows and the sky is near white (sample tutorial).

Fix the sky first with highlight recovery until the clouds come back. Then use shadow lift for the faces. Doing it in this order stops the faces from turning grey.

If the faces still look flat, add a subject mask and raise the midtones inside it only. The sky stays exactly as you left it.