The tvOS SDK is based off of iOS, but is not interchangeable. Unlike when the first iPad was released, the new Apple TV will not be capable of running iOS apps.
The AppStore for the TV will only include apps built specifically for tvOS.
For any iOS developers looking to create apps for Apple TV, I’d recommend checking out the new documentation page: https://developer.apple.com/library/content/documentation/General/Conceptual/AppleTV_PG/index.html#//apple_ref/doc/uid/TP40015241-CH12-SW1
Specifically, check out the Inherited iOS Frameworks section to give you a sense of what will work out of the box from your existing iOS projects.