In Secret Level there could have been a crossover between Doom and Halo, but Microsoft said no

In a new interview with the website Collider, Tim Miller, one of the creators of the anthology series Secret Level of Prime Video, revealed that he had thought of an episode that would feature the Doom Slayer from Doom and Master Chief from Halo together.
Speaking to Collider, Miller explained that he had an idea for a crossover between these two popular first-person shooter series. However, to have said no to the proposal from the authors of Love, Death & Robots would have been Microsoft itself.
“I get a little irritated when I read comments online and they say, ‘Wait, these guys got Spelunky when they could have gotten Halo?’ Or something like that,” Miller said. “I say, ‘Man, do you think we didn’t think about Halo?'”
“The creative director at id Software is a good friend of ours, as well as some at Microsoft, so we appealed to them since one of the things that both Tim and I would like to do is really crossovers,” added co-creator Dave Wilson.
“We wanted to do a crossover episode between Master Chief and Doom Slayer, and I spent a whole weekend writing this passionate letter from my childhood. And that’s exactly what Tim said; they said, ‘No,'” Wilson continued.
The first season of Secret Level is now available on Prime Video, and a second season has already been confirmed. What titles will be featured in the next Secret Level series, however, is still a mystery.