Hey @brash-bird-53526, within a cluster (or between clusters), we typically run Linkerd/Envoy and enable mTLS there. This ensures traffic from/to flyteadmin is Encrypted.
However, from a "public" client (i.e. a client running on an end user's machine), we rely on SSL on the cluster ingress to encrypt traffic to the cluster. And on Auth (SSO comes out of the box) to authenticate the caller.
There isn't a doc on enabling mTLS, support will need to be added to the gRPC server to load/roll/fetch/refresh client certificates... etc. I think from separation of concerns perspective, I would do delegate this responsibility to a proxy & a rev proxy on the client side.