You don’t play Sombra. You wouldn’t know how much teamwork matters.
If I hack a Reinhardt I EXPECT my team to take advantage of it, and if they don’t despite me doing it over and over, nothing is going to happen. If I EMP and my team doesn’t push it, I just wasted my ultimate because of my team.
If Mercy pulls off Resurrect then ta-da nothing else required. Any teamwork for res is maybe putting a shield in front of Mercy? Even then your teammate probably died in a terrible position and resurrecting them was a bad idea in the first place.