Beautiful cherry tree dropping leaves like fall. What should be done, if...
You are seeing the symptoms of cherry shot hole disease. Wet spring weather is ideal for the development of this disease and we have had a lot of questions about this recently. Both a fungus and a bacterium can cause shot hole disease in cherries, and distinguishing between the two pathogens is challenging. Neither will be controlled by sprays applied after symptoms have progressed to this point. Some defoliation also occurs as a result of this condition.
The good news is that trees produce many more leaves than they need to feed themselves via photosynthesis, and in most cases mature trees can sustain some of this damage and recover in future years. No treatment is recommended. Remove and dispose of fallen leaves to reduce fungal inoculum around the planting area. This does tend to be a chronic issue in cherry trees in this area, and it is typically worse in wet weather years. Here is more about cherry shot hole and how to manage it. https://extension.umd.edu/hgic/topics/cherry-shot-hole-flowering-cherries
Right photo - The tree looks like a telephone pole coming out of the ground. It is possible the tree maybe planted too deeply or overmulched. Makes sure mulch is no thicker than several inches and away from the base of the trunk.
Root collar excavation, which is the removal of excess soil and mulch around the root collar (base of the tree), can sometimes be helpful. Carefully remove the excess mulch or soil from the circumference of the trunk to the point where the trunk flares out into root growth. Here is more on planting too deeply and excess mulch.