Fetch is a Web API, not an ECMAScript language feature, so TC39 doesn’t have much to do with it. They do do Promises though and Cancellation is a Stage 1 proposal [0], so it’s more than a year away from standardization at best.

WHATWG handles Fetch and their spec[1] was updated seven days ago.

[0] https://github.com/tc39/proposals/blob/master/README.md [1] https://fetch.spec.whatwg.org