Pokémon GO launched with the ability to track wild Pokémon, but it proved to be glitchy and developer Niantic later removed it. Since then, they’ve been testing out a tracking feature (called the Nearby Pokémon feature) in beta form in the San Francisco area. Although they recently stated that there is no estimated timeline for taking this feature worldwide, they’ve just expanded it to include parts of Arizona, the Seattle area of Washington state, and the rest of the San Francisco Bay area. Hopefully this means a global rollout is on the way in the near future.
Trainers in parts of Arizona, the Seattle area of Washington state, and the rest of the SF Bay area can now test the Nearby Pokémon feature.
— Pokémon GO (@PokemonGoApp) November 5, 2016