Black cherry aphids are common on cherry trees, and some years they can really impact a crop. This Hortsense article gives specific control measures. Once the leaves are curled, it’s generally too hard to reach the insects to wash off or chemically treat, so timing is everything. Be ready to act next spring. If your tree is large you’ll likely need to hire a professional.
Regarding the leaves now, you could prune off a few badly distorted twigs. There isn’t really much reason to worry about it though, as soon it will be fall and the leaves will drop off for the winter.