Xfinity Stream not showing as an app on a firestick

I have just purchased a new firestick through Amazon and have attempted to download the stream app on my home network.  When I type in the app store, it doesn't come up as an option, instead listing other streaming options.  I have downloaded other apps, so I know it is not a network issue.  Can someone point me in the right direction here? I am located in Hillsborough, New Jersey.  I did see some comments about regionality blocking, but I am not sure why this would be the case.  Thanks!