Are Ultra Beasts coming to Pokémon GO next Season?

A teaser has been released on the official Pokémon GO Twitter feed revealing Nihilego will be the first Ultra Beast to be introduced to Pokémon GO. At the
Niantic and The Pokémon Company have teased that Gen 7 Ultra Beasts are on their way to Pokémon GO - look out for Wormholes!

How to take on Nihilego in Pokémon Go - Dans Tutorials

Pokémon Go Ultra Beast Buzzwole for PvP Ultra league or Master league

😲SURPRISE ultra beast RAIDS in pokemon go.

Pokémon Go adding Ultra Beasts as Season of Alola comes to an end - Polygon

The reports are in—a surge of Ultra Beasts is approaching! – Pokémon GO

Pokémon TCG: Ultra Beasts GX Premium Collection (Pheromosa & Celesteela)

Pokémon Go teases Ultra Beasts addition next month

ULTRA BEAST ARRIVAL – Pokémon GO

Ultra Beasts Are Coming to 'Pokémon GO' Very Soon