Marvel's Moon Knight and DC's Batman have a lot in common but Marc Spector's humor sets him apart from the Dark Knight
If we're going to count the characters that Marvel and DC have ripped off each other, it would fill multiple books. From Deadpool to the Atomic Skull, there's been quite a bit of "exchange of ideas" between the two publishers.
To the casual observer, Moon Knight/Marc Spector and Batman/Bruce Wayne may seem like another case of Marvel being "inspired" by a DC hero. They're both ordinary humans with vast fortunes who use specially designed gadgets to wage a nightly war on crime in their hometowns. Plus, they both have a flair for the dramatic, a love for capes, and an extremely violent disposition.
That's not to say they don't have important differences though. Bruce inherited his fortune after the death of his parents while Marc made his money back when he was selling his services as a mercenary, long before he became the so-called Fist of Khonshu. Batman's sanity is something the character holds very precious while Moon Knight is as disturbed as they come.
However, the real difference between the two characters lies in their sense of humor. Batman might occasionally make a snide remark or let a smile shine through but generally speaking, he's not the sort of person you'd want to see take the stage in a comedy club. Moon Knight isn't exactly a joker but he has a certain dry, dark humor that adds a comedic layer to this bizarre character.
From crashing a helicopter into a building as revenge for an attack on his pilot to cutting off his arch-enemy's face and wearing it like a mask, Moon Knight has done a lot of things in the comics that would seem completely psychopathic outside of the right context. In the right context though, this psycho vigilante is a riot who could give Rick Sanchez from 'Rick and Morty' a run for his money when it comes to dark twisted comedy.
Moon Knight will soon be joining the Marvel Cinematic Universe by appearing in his own eponymous Disney+ series. The show doesn't have an official release date yet but it is expected to arrive in either 2021 or 2022.