PHP 7.4
While everyone else (well, me) have their attention on the hippest, newest languages PHP has been steadily improving, getting faster, and still runs a lot of the largest web properties. It wouldn't surprise me if before long PHP can be compiled to native binary* complete with a memory efficient, non-blocking web server and performance approaching what Go and dotNetCore can achieve... and the option to emit a "normal" PHP web app that can run anywhere if you don't need Facebook-level performance from it.*I realize HipHop PHP did this already but it doesn't have it's own baked-in web server afaik. I'm thinking along the lines of compiling down to something small and fast to be deployed to K8S clusters without needing containers for Apache or nginx as part of the setup.