For those unfamiliar with universal search, it is a feature that lets users conduct Siri voice searches or text-based searches to find TV and movie content across a wide range of apps. At launch, universal search supported only a few apps, but Apple has been adding new apps on a regular basis.
With the addition of support for Comedy Central, MTV, and VH1, searching for shows available on those networks will now bring up options to watch content within the respective apps.
Apple maintains a dedicated support document that offers Apple TV owners a full list of content that can be found via Siri through universal search. Apple’s universal search feature is largely limited to the United States. In most other countries, universal search only displays iTunes content, while Netflix is also supported in Australia, Canada, France, Germany, and the UK.
Source: Mac Rumors