To sort by more than one thing, make the key return a tuple. Tuples compare item by item: first by the first item, and only if those are equal, by the second:

people = [("Ada", 36), ("Bo", 25), ("Cy", 36), ("Di", 25)]
print(sorted(people, key=lambda p: (p[1], p[0])))
print(sorted(people, key=lambda p: (-p[1], p[0])))

The second line sorts by age descending (negating a number reverses its order) and then by name ascending.

Python's sort is also stable: items that compare equal keep their original order. That lets you sort by one thing, then by another, and the first ordering survives within ties.