Deploying microservices to Kubernetes (and other cloud-native platforms) is only easy in theory. The inherent complexity of distributed systems requires new techniques of observability, analysis and resilience. Service mesh is an infrastructure-based architectural pattern that makes these techniques possible in a smart, centralised way. Leaving the services fully ignorant. Like: "I'm a service, I don't care about the platform. I just wanna serve information."
Istio is an open source service mesh initiated by Google, IBM and Lyft, providing the services with this option of blessed ignorance. Let's see what it gives us (engineers) and what it deprives us of.