I create this end-to-end guide and an example on how combine Traefik with Pomerium.
For those who don't know it Pomerium is an "Identity-aware Secure Application Access Proxy to Authenticate, authorize, monitor, and secure user access to any application without a VPN"
From past discussion here some recommended solutions where [thomseddon/traefik-forward-auth] or forks of that. I personally think Pomerium is the most versatile and powerful solution out there today, especially if someone is on Kubernetes. Pomerium doesn't yet have a ton of documentation, hence this guide.