Interlisp is very different from Common Lisp; back before the standardization process happened, Interlisp and MacLisp were the two main competing branches of lisp. During standardization the MacLisp people won and Interlisp has been mostly forgotten. (until one game jam contestant decided it was time it made a comeback!)
This HOPL paper on early lisp history is pretty fascinating; I learned a ton: https://doc.lagout.org/programmation/Lisp/Lisp%20Mess/Gabriel%20%26%20Steele%20-%20The%20Evolution%20of%20Lisp.pdf