How to ask Siri to tell me the news
The News app and features for iOS 10 are only limited to the USA, UK and Austraila at the moment. http://www.apple.com/ios/feature-availability/#news

In these countries, if you were to ask Siri for example:


  What's the latest in New York City


Sir would respond with a list of articles from the News app. 

However, if you are outside these countries. For example, I am in Toronto, Canada and if I ask Siri a similar question: 


  What's the latest in Toronto


Siri first asks for confirmation to use a Twitter account to recommend more personalised results if you don't have one signed in or don't allow Siri access to Twitter. Siri will display a list of Tweets related to the location of Toronto.