Recently I searched for a movie within the Apple TV app. The result is that it is available on Netflix. But I also had the option to add to up next.
I thought Netflix did not support the tv app’s up next feature?
In addition to what @JBaby has said, if the content on Netflix is also available through another source you will be able to add what you're looking for to Up Next. For example, Sherlock is available on both Netflix for streaming and the iTunes Store for purchase. However, the TV app won't track your watch history if you watch it on Netflix.