There is https://github.com/copilot-emacs/copilot.el that gets copilot to work in emacs via JS glue code and binaries provided by copilot.vim.

I hacked up a slim alternative localpilot.js layer that uses llama-server instead of the copilot API, so copilot.el can be used with local LLMs, but I find the copilot.el overlays kinda buggy... It'd probably be better to instead write a llamapilot.el for local LLMs from scratch for emacs.