https://wccftech.com/cod-black-ops-4-zombies-issues/

For years, Zombies mode was not-so-secretly the main focus of Treyarch’s Call of Duty games. The studio devoted a ton of care and effort to Zombies, transforming something that started as a minor Easter egg into a rich, fan-favorite experience. Unfortunately, it seems Treyarch’s devotion to Zombies has waned with the release of Call of Duty: Black Ops 4.

Since Black Ops 4’s release, Zombies fans have complained of technical issues, including game-ending crashes and other bugs that impede progress, and fixes have been slow to arrive. Playing Zombies also doesn’t contribute to Black Ops 4’s new Contraband progression system. Overall, the feeling is Zombies has got the short end of the stick this time around, which is a shame, given the mode has been such a core part of Treyarch’s CoD games in the past.