There are shrubs growing along my back fence (SE Denver) and one in my yard per se, which when I key it out on the Extension service website, it says it is a common choke cherry (https://bit.ly/3qwhLsE). However, my neighbor disagrees and after looking at the photos online I have to concur.  Most are roughly 6 feet tall, fairly open, but one along the fence line is maybe 12-15 feet tall, and the shrubby one in my yard I trim to semi-round shape about 4 feet talk. The flowers are all gone, but as I recall they are white or possibly light pinkish white (I just can't remember). The berries here typically come in twos and threes, close to the branch, not in hanging clusters. They are about the size of a standard peanut and white or whitish green, turning mottled orange and then red (most are turning now, at the end of June). In spring there typically are gazillions of little ones coming up, which I think are these shrubs, from fruits that have fallen off are spread by squirrels, which seem to like them.

For all the world it does look like choke cherry, but the cherries are not quite right. I've had suggestions from Korean Cherry to Nanking Cherry to Flowering Almond. None seem quite right. Any ideas?