Gateway API is an open source project managed by the SIG-NETWORK community. It is an API (collection of resources) that model service networking in Kubernetes. These resources —
GatewayClass,Gateway,HTTPRoute,TCPRoute, etc., as well as the KubernetesServiceresource - aim to evolve Kubernetes service networking through expressive, extensible, and role-oriented interfaces that are implemented by many vendors and have broad industry support.The new Gateway APIs aim to take the learnings from various Kubernetes ingress implementations, including Istio, to build a standardized vendor neutral API.

Google Kubernetes Engine Gateway controller is now GA | Google Cloud Blog
The GKE Gateway controller, already GA, is Google Cloud’s implementation of the Gateway API for GKE clusters: