Hi, A Cilium contributor here.

There is a native integration with Istio, you can read tested at the following url: http://docs.cilium.io/en/doc-1.0/gettingstarted/istio/

Last week was the Kubecon Europe, Thomas Graf, founder of the project, presented some new improvements made in Envoy and TLS integration. Here are the slides:

https://schd.ws/hosted_files/kccnceu18/d9/2018%20KubeCon%20E...

Regards