Istio is a service mesh implementation.
I'm afraid so...
You sorted out Docker and Kubernetes. You have re-architected your application to be cloud-native. Job well done, pat on the back and all that. Now if only you could make a sense of the spaghetti mess you have created. Everything sorta works but you have no idea why!
"Oh dear monolith, how I miss you" you cry every time you are tasked with investigating a production issue.
This is the time you must fight the urge to go back to the monolith and invest your efforts into a service mesh such as Istio.
A service mesh is a collection of tools that surround your microservices, helping them, routing requests and responses, providing traceability/observability and much more.
"Now you have N problems".