Consul 1.8 introduces WAN federation, allowing multiple Kubernetes clusters to be connected securely across various environments. This enables cross-cluster communication between services without the need for complex networking configurations. By leveraging Consul's mesh gateway feature, users can deploy a backend service into one cluster and a frontend service in another, while establishing secure communication between them using encrypted traffic over the internet. The process involves deploying Consul to two Kubernetes clusters, configuring WAN federation, creating pods that register as Consul services, and setting up intentions to allow traffic between services. This approach provides a scalable and secure solution for connecting multiple Kubernetes clusters across different environments.