The first expansion pack of Cities Skylines will focus on the night time cycle that your city experiences.
The day to night cycles were announced as part of the After Dark expansion pack, which will allow your cities to take on new characteristics as the night falls. This is much more that just a cosmetic change as the city will function differently at night. Traffic may be reduced in certain areas and citizens will play differently as the night goes on.
The expansion will also add a new leisure specialization, which will be busier at night but act normal during the day.
Services are being added too as well including taxi service for citizens, prisons for criminals to be taken to from police stations, international airports , and bus terminals that transfer citizens from one bus line to another.
Bikes are also being added, along with dedicated bike lanes and paths, and bus paths to improve the efficiency of public transport.
The expansion has no release date thus far, nor do we know if the content will be available for the Xbox One version of the game.