With the release of the preview version of Windows 9 on September 30th, Cortana will be made available in desktop also which was already present in the Windows 8.1 phone update. The evidence of the presence of the personal digital assistant of Windows was already found through various leaked images of a certain build.
Cortana is supposed to have all the features on the desktop as well which are already present on the phone and since it will have access to more of your contents, i.e., if you allow access to it, and can monitor the way you work; it will be able to understand your preferences better in undertaking your daily tasks and predicting what would you do next.
Microsoft will help in bringing Bing to the customers where Google is already dominating the search engine market. Along with updating you with the daily traffic, news, weather, sports and getting you notifications and reminders Cortana will be an integral part of Bing. When users will be using Cortana and give commands to it to search for a query, it will perform a search through Bing search engine and display results accordingly. The motive behind this is to prove to the world that Bing is no less than Google in addition that Bing provides unique features except search. If given access to Cortana, it will analyse your search patterns and build a profile specific to you to get more accurate results.
Another functionality that is likely to be added to Cortana is to perform search within your local content such as finding a document in your device. More updates will be added in the next builds as Microsoft updates the features of Cortana twice a month and helps it to get smarter.