I’m not sure what a “leo laser” is. As for firmware support, the last I saw on the forum, laser was enabled on the Rambo firmware and the SKR Pro firmware, but it was not enabled for other boards. I believe it was enabled in version 509 (current version is 510). If you don’t have one of these two boards, you can do a diff between the configuration.h and configuration_adv.h of the Rambo version of Marlin and your version of Marlin to see the differences.
Ryan outlines his laser testing and provides a test g-code file in this topic.