Apple Maps gained a Transit tab in iOS 9. The feature lags several years behind Google Maps, but Apple's public transportation support is exhaustive, mapping all station entrances and listing departure times.
At launch, the feature was limited to Baltimore, Berlin, Boston, Chicago, London, Los Angeles, Mexico City, New York, Philadelphia, San Francisco, Sydney, Toronto, and over 300 cities in China. Since then, Apple has been working to expand support for public transportation to other cities around the world.
Newer additions include Atlanta, Columbus, Dallas, Denver, Detroit, Honolulu, Houston, Kansas City, Manchester, Melbourne, Miami, Minneapolis–Saint Paul, Montréal, New Orleans, Paris, Portland, Pittsburgh, Prague, Rio de Janeiro, Sacramento, Salt Lake City, San Antonio, San Diego, Seattle, and Vancouver, B.C.
A complete list of cities that support Transit in Apple Maps is available on the iOS Feature Availability page of Apple's website.