Niantic finally going to release the next big update and event for the Pokemon GO and you can try to hunt down the legendary pokemons. The hunting is not for the solo players. Players will have to work together to defeat the rare monsters using the game’s new cooperative raids feature.
Once in the wild, trainers can search for unique legendary eggs at gym locations around the world, … Players can team up with friends and other trainers to join legendary raid battle to defeat the legendary pokémon and earn a chance to catch it.
The first legendary pokémon raid will take place during Pokémon Go Fest in Chicago on July 22nd. After that all over the world (includes Japan, Europe) you can try it from July 23.