Clojure uses the underlying host's GC (e.g., JVM, CLR or JS engine). It also typically generates rather more garbage than other languages may due to immutability by default. As with all things, you can avoid the garbage if you are willing to abandon the usual idioms.

I heard Allegro's GC is concurrent and that "a new GC seems to be brewing in SBCL".

Also Clasp's GC (via Boehm GC and MPS).

Last but not least, quoting: "when one runs ABCL on a suitable JVM with ZGC or Shenandoah, then it has parallel GC".

https://twitter.com/stylewarning/status/1387809546287022082?...

https://lisp-journey.gitlab.io/blog/pro-mailing-list-on-comm...