Cherry tree in trouble
Based on your 1st picture I suspect your tree cherry leaf spot, a leaf spotting fungal disease that causes them to drop prematurely. Sweet cherries are more resistant than tarts, but still can have problems.
More siignificant is the gumming and dead limbs. I assume by honeydew you mean gum. January 2019 low temperatures were tough on a lot of trees of various types and ages. The result is damage to the cambium under the bark. Insect can find weakened trees, speeding the decline. If the gumming was severe and reoccurs in 2021, this indicates to me that the tree is in decline.
Do modest watering when the ground is obviously dry. Do modest pruning next spring to remove some of the fine wood and let light into the tree. This will help stimulate new growth and help get light inside the tree.