Azure utilizes Defender as protection for a variety of different services within the platform. Kubernetes is a deployment tool created to automate and assist with deployments.
Any service with a Defender offering should always take advantage of the benefits, it is recommended that this be turned on. There is the possibility that enabling an anti-virus program interferes with particular software, if so, its should be investigated and configured to coincide properly. More information about this can be found from Azure: https://docs.microsoft.com/en-us/azure/security-center/defender-for-kubernetes-introduction