I don't think it's a gall per say, but it is an abnormal grow of some sort, which could potentially girdle and kill the branch. Seen them on some pines -- perhaps someone else can pipe in w/the cause.

It is a gall - pine gall rust caused by the fungus Endocronarlium harknessii. It is quite common to Pinus contorta. This link should explain it thoroughly and offer suggestions for possible treatment. https://www.fs.usda.gov/detail/r10/forest-grasslandhealth/?cid=fsbdev2_038389

@gardengal48 (PNW Z8/9): thank you, I think I will remove it. I noticed one on the bole. And I don’t want this to spread to my other pines.

The disease is restricted to 2 or 3 needled pines. And Pinus contorta is often the first species mentioned so perhaps more susceptible than most other vulnerable species.

I see those all the time on P. banksiana.

I don't know if I've ever seen a single dead branch but I suppose eventually that will happen.