Zig doesn't currently have async/await in the sense that this post is about (i.e., async/await based on stackless coroutines). It previously had this, but it was removed last year (https://ziglang.org/download/0.15.1/release-notes.html#async...).

The 0.16 release earlier this year introduced a much-heralded userland API (https://ziglang.org/documentation/master/std/#std.Io) that can be used to implement various asynchrony and concurrency patterns, including green threads, but it can't do stackless coroutines because support for those has to be baked into the compiler.

There is currently an open proposal to bring back stackless coroutines without dedicated syntax (instead offering low-level bring-your-own-buffer APIs for interacting with suspended coroutines), which could be combined with the aforementioned userland API to produce something more like how async/await works in other languages (https://github.com/ziglang/zig/issues/23446).