[qazwse_]

I haven't used it, but I know that Coalton adds static typing to Common Lisp, might be something you're interested in.

https://github.com/coalton-lang/coalton

[packetlost]

I'm more into Scheme than CL, but am aware of Coalton. My current lisp is Gerbil: https://cons.io which already has a type annotation system and will be enhancing it for the next major release (v19).