How to provide for 2 different IP ranges? --pod-network-cidr= for multiple IP ranges
--pod-network-cidr is for IPs of the pods that kubernetes will manage. It is not related with nodes of the cluster.
For nodes, the requirement is (from Kubernetes doc):
Full network connectivity between all machines in the cluster (public or private network is fine)
In addition to @Yavuz Sert answer, --pod-network-cidr flag identifies Container Network Interface (CNI) IP pool for Pods communication purpose within a Kubernetes cluster. You have to choose some separate IP subnet for Pod networking, it has to be different against your current given network sets. Since --pod-network-cidr has successfully applied kube-proxy reflects Pod IP subnet and add appropriate routes for network communication between Pods through cluster overlay network. Indeed you can find clusterCIDR flag withing kube-proxy configmap which corresponds to --pod-network-cidr.