There are many possibilities including:

1). Our wet weather has led to the appearance of several fungal diseases. The most common of which is brown rot, caused by Monolinia fructicola and Monolinia laxa. Both can cause cherries to rot on the vine. Infected cherries often show brown, soft spots that rapidly expand, leading to complete fruit rot. There is probably little that you can do in 2024 to save your cherries if this is the disease with which you are dealing. Your emphasis should be on preventing a recurrence in 2025. See the following for more information including remedial procedures. At this site look at the picture showing a cherry with small, yellowish bumps on it. This looks very much like a cherry in the picture you sent.

https://extension.umn.edu/plant-diseases/brown-rot-stone-fruit

2). There are various bacterial diseases such as bacterial canker caused by Pseudomonas syringae. Infections can lead to fruit rot. Symptoms include dark, sunken spots on the fruit. See the following for a picture of what this canker looks like:

https://extension.psu.edu/cherry-disease-bacterial-canker

3). Also, the prolonged wet conditions that we have been having create a favorable environment for fungal and bacterial growth, leading to rot.

At this point, I am inclined to think that your tree has brown rot. However for a certain resolution to the matter, there are two directions you can take, either or even both, will provide you a good answer to what is going on

1). Consider submitting plant samples to a diagnostic disease laboratory for an analysis. This would be a definitive way of getting to the bottom of things. Both Wisconsin and Minnesota have excellent labs to do this. Before submitting anything to either of them, call first as to what type of samples should be submitted. Both have a nominal charge for their analysis. See:

https://pdc.umn.edu/

https://pddc.wisc.edu/clinic-overview/

2). A professional, licensed arborist could make an onsite examination and assessment. See:

https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional

Good luck. Please get back to us with any further, related questions. Thanks for consulting with us