Per Richard Donner’s comments from two years ago, Lethal Weapon 5 is called Lethal Finale, and he described it as being a “very dark” and emotional conclusion to the film series. Channing Gibson was working on the script back then, but it’s unclear if his drafts are still being polished or if someone else was brought in to tackle the story. Who knows, maybe original writer Shane Black could be involved somehow. After all, he did pen his own Lethal Weapon 5 treatment long ago.
Article source: https://www.cinemablend.com/news/2489255/sounds-like-lethal-weapon-5-is-happening-after-all