If you don't know anything about Kubernetes this is a good start. Read it to learn about the architecture, components and basic actions in Kubernetes:
There are several possible Kubernetes services that you could find exposed on the Internet (or inside internal networks). If you find them you know there is Kubernetes environment in there.
Depending on the configuration and your privileges you might be able to abuse that environment, for more information:
If you manage to compromise a Pod read the following page to learn how to enumerate and try to escalate privileges/escape:
You might have managed to compromise user credentials, a user token or some service account token. You can use it to talk to the Kubernetes API service and try to enumerate it to learn more about it:
Another important details about enumeration and Kubernetes permissions abuse is the Kubernetes Role-Based Access Control (RBAC). If you want to abuse permissions, you first should read about it here:
If you have compromised a namespace you can potentially escape to other namespaces with more interesting permissions/resources:
If you have compromised a K8s account or a pod, you might be able able to move to other clouds. This is because in clouds like AWS or GCP is possible to give a K8s SA permissions over the cloud.