Editing Warhammer 40,000/Tactics/Kill Team(8E) Guide and FAQ (section)

==Which missions can I use the models/rules from Kill Team: Elites in?==
Literally all of them. They're always in play unless you specifically house rule them out.

There is no "Elites" game mode like Commander or Ultra-Close Confines (i.e. Arena), but rather the book is an an expansion on the core rules. Thus the models it adds are available in any and every type of mission, including those other game modes, as are most of the new rules*. 

The book has missions in it, but these are just extra missions and you are not required to play those missions to use the new rules and models, nor to use the new rules and models if you play those missions.

<small>*The one exception is that you cannot use the Reserve rules in Ultra-Close Confines (i.e. Arena) missions as specified in the Reserve rules. Everything else is fair game, including subfactions.</small>