Nissan recently tweeted that its upcoming CES announcement will involve Cortana, Microsoft's personal assistant. Below I offer some background about Nissan's partnership with Microsoft and its possible implications for the future of Nissan cars to provide a context for the upcoming announcement. 

• At CES 2016, Nissan announced a partnership with Microsoft to use Microsoft Azure, the collective name for Microsoft’s cloud services. Through the partnership, Microsoft Azure provides navigation, predictive maintenance, remote car monitoring, and over the air updates for Nissan’s electric car model, the Leaf, and Infiniti models.
• Nissan’s partnership with Microsoft also extends to its Leaf model’s operating system—Microsoft Windows Embedded OS 7. It would not be surprising for the Leaf also to receive Cortana’s capabilities. Cortana already forms the foundation for Kia’s UVO voice recognition software in Kia vehicles that run Windows Embedded OS 7. In addition, Microsoft made integrating Cortana easier for automakers in September 2016 by releasing an SDK that enables Microsoft’s partners to create new skills by using Microsoft bots or repurposing Amazon Alexa’s skills.  
• In addition to providing voice assistance, Cortana can be used with Microsoft Azure to provide personalized experiences for Cortana users. By pairing information supplied to Cortana with Microsoft’s understanding of the vehicle’s context, Azure’s data analysis can develop insights into user preferences that will help automakers like Nissan provide personalized services to their passengers. 
• The partnership with Microsoft may be a move by Nissan toward providing additional productivity services in autonomous vehicles. Nissan plans to release autonomous city-driving cars by 2020—the earliest date announced by any traditional automaker for public availability of its autonomous vehicles. If Nissan is still on schedule, its autonomous cars are already beginning the production process. Automakers, knowing that autonomous car production would begin soon, have discussed how to allow passengers of autonomous vehicles to be more productive during their trip. One productivity offering was announced by Harman at CES 2016: Harman enables Microsoft Office 365 productivity suite integration into autonomous vehicles. As part of its extended relationship with Microsoft, Nissan may also plan to incorporate Microsoft's Office 365 Suite into its autonomous vehicles. Microsoft’s productivity suite allows passengers to setreminders, schedule meetings, respond to emails, manage calendars, and hold Skype calls. In the future, we may very well see Nissan enable all of these activities through Cortana. 

Further Reading:

• App Strategies for the Connected Car Industry
• Cloud Platforms Reshape the Value Chain for Connected Devices
• 58% of U.S. car owners very concerned about hidden fees for connected car services