Q.Why My Dwarf Cherry Tree Has Not Grown Many Leaves
It has bloomed and fruit has come in

Certified GKH Gardening Expert
It does seem stressed. I would take a soil test, or have it tested by professionals. After, it will likely show a nitrogen deficiency. If so, then an application will be necessary.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
https://www.gardeningknowhow.com/edible/fruits/cherry/cherry-tree-care.htm