Control Plane is a group of components to run the cluster; Data Plane is everything that is actually the app and things supporting the app. It's like the Control Plane is the OS and the Data Plane is the app running on the OS.

Control Plane — manages Kubernetes clusters and the workloads running on them. Include components like the API Server, Scheduler, and Controller Manager. This is like the "manager".

Data Plane — machines that can run containerized workloads. Each node is managed by the kubelet, an agent that receives commands from the control plane. These are the employees the "manager" manages.

In "KinD", it creates one docker container by default and puts everything in there, so that confused me at first. If you think of the control plane as the "main" node and any other node is part of the "data plane" that helps. The graphic here helps.

As always: This is for my own understanding. It might be wrong but reflects my current understanding.