Cherry leaves tend to get a bit 'ratty' this time of year. Brown leaf tips can be lots of things. First guess is water was left hanging on them overnight since they tend to hang tips down. If this makes sense, you should try to not sprinkle the foliage when you water them. It is sometimes hard to avoid, so can also spray with 2 tablespoons hydrogen peroxide (from the grocery/pharmacy) in a quart of water right after watering. This solution is an eco-friendly, broad specturm fungicide/antiseptic.
Brown tips with browning extending also along the margin is the usual result of the tree having gotten too dry a few days ago. Black gooey tips are sometimes the result of the opposite.
At any rate it is often difficult to tell whether it is fungal or not. No fungicide, barring possibly a systemic, will cure infected tissues; they will only nix spores on the surface. Peroxide acts only on what is present at the time and becomes nothing more than water. Commercial fungicides like Daconyl leave a residue that will nix any incoming spores for a week or two or until rain (or watering) washes off the residue.
Once infected, the leaf becomes just a spore source, so the SOP is to remove the affected leaves and spray. I think it a good course to follow until you know what is really happening if it isn't fungal.