The new React Query client is a powerful data fetching library built on top of TanStack React Query, allowing developers to consume WunderGraph queries, mutations, and subscriptions with a typesafe API. The client offers features such as conditionally fetching data, building real-time apps with subscriptions, and invalidating queries. It provides an easy-to-use API for optimistic updates, similar to the SWR integration, which can be used in React applications. The client currently supports React but is planned to add support for other frameworks like Vue, Solid.js, and Svelte in the future.