Hi Everyone – thank you for your patience. As was commented by someone below, Suphatra is no longer at Microsoft, but rest assured we are working on this feature.
~ AlexDavid Costar commented
Channel level security is a significant gap that limits the full usage of Teams. Having a Teams site for an enterprise-wide department is effective, but not being able to limit specific artifacts and sensitive information to a few within that department continues to be an issue.