Say you want to learn Rust, but all your experience is in Javascript. Most recruiters will immediately filter out your resume if you don't have the keyword "Rust" somewhere in the document.
Before you start sending out your resume, spend a few weeks hacking on a Rust side project to learn some of the basics. Then on your resume, include a description at the top saying you're proficient in Javascript, but want the opportunity to work in Rust. Then include a "Side Projects" section at the bottom that lists your Rust experience.
I've landed 3 jobs that way, where I'm hired for my experience with X, but under the condition I will have the opportunity to learn Y. Otherwise, it's easy to get trapped working with the same tech at a new job, and your skills eventually become obsolete over time.