The devs gave an explanation.
Last year, Call of Duty allowed Battle Royale into their games with Black Ops 4. The mode named Blackout has fans curious for the next installment. Will there be a Battle Royale mode in Call of Duty: Modern Warfare too?
Joe Cecot, the multiplayer design director of Infİnity Ward responded by saying there won't be a Battle Royale mode in the upcoming Call of Duty title. He says that they've thought of a lot of different options for Modern Warfare but in the end, arrived at this conclusion. "We're big fans of battle royale. We're excited for large player counts and things like that, but right now we're really focused on core multiplayer." stated Joe.
Joe touched upon their current mentality about multiplayer. "We really focused on Modern Warfare, authentic and gritty, realistic weapons and it's a different experience. It's really... just about pulling back to Modern Warfare and keeping that pure." Accordingly, they are returning to Modern Warfare dynamics which players have been longing for.