I would have to say that, no matter what framework, methos, process, or approach a group of people are placed in, Trust is mandatory for totally successful results.

The other two things that would have to go along with Turst would be Communication and Collaboration as the three of them require one another for totally successful results.

Trust requires that you communicate and collaborate effectively.

Communication require that you collaborate and trust effectively.

Collaboration requires that you communicate and trust effectively.