To me it looks like blight. This issue seems to occur when the plant is flowering. It can be fungal or bacterial. Bacterial blight is common in many areas and is difficult to control. The plant will look fine until blossom time then shortly afterwards the branches infected thru the flowers will shrivel up.

First line of defense is to prune out infected parts of branches to stop the spread. If you prune early you can save some of the branches. Do sterilize your pruners between branch cuts.

The next line of defense is to spray the following year while the plant is dormant with copper or chlorothalonil. The 3rd thing to do is spray at white bud stage (when flowers show white but not yet opened).

I did all this and it still wiped out my North Star cherry after 3 years. I slowed it down but in the end it won. Now my Surecrop cherry has it. If what you have is blight (bacterial or fungal) I wish you the best trying to control.