Pokemon GO is a few Pokemon short of a full roster. It was a smart idea to hold the legendary ones back. It helps make sure players are interested in the future. But when is that future? We know that Niantic is planning on big events in the future. The most speculation is on whether or not the legendary birds will make an appearance at these events.
Unfortunately, speculation is all we have right now. And even that is lacking. We don’t really have an idea how that would go down. It’s no surprise that each team is based off of one of the legendary birds. So it could be a team event connected to the birds somehow. And that’s assuming they’re appearing at these events in the first place. Since its launch, Niantic has been tight-lipped about what’s coming up.