Is it wet or dry? If it’s wet and oozing, probably is. I had that on a nectaplum, dug it out and painted it. That has really helped, at least so far.
It’s dry! Not oozing, but it looks like it was oozing at some point. Been checking it daily for the past week. Hasn’t changed much if at all. I guess that’s a good sign?
Nothing there looks too obviously canker to me. It tends to get darker and ooze more when its canker. Do keep an eye on it.
Speaking of canker I remembered I have one to cut out of a cherry tree that I noticed for the first time yesterday.