Looks like some type of mold or virus, I study agricolture but I’m no expert on cherry trees
Edit: looks like apical mold to me
Is there a cure for apical mold? The whole tree looks like that.
Your best bet is to stop watering it and put it in dry place and if you are willing to put down some bucks you could buy a fungicide and spray it on every leaf not just the infected ones
Never watered it.Its is a big tree. Its just a cut off branch on the picture
Was it very humid lately?
Not lately but some time ago 4 weeks rain every day
That is for sure the cause, try the fungicide
Maybe lot of water to it. Tomatoes are suggestive to create fungus with humidity
It rained a lot over here in early spring. And the ground is sandy
That is probably…sadly is something it happened to me a lot…