A new Call of Duty: Black Ops 4 update recently went live alongside the game’s first 2XP weekend event, Black Market, and Halloween event. It adds leaderboards for multiplayer, Blackout, and Zombies, and brings with it a number of fixes and improvements.
Patch notes are as follows:

General

Leaderboards are now available for Multiplayer, Blackout, and Zombies. For Multiplayer and Blackout, players will start ranking on Leaderboards after playing 25 games.

Addressed an issue where player-created paintjobs may appear corrupted or stretched when placed on weapons. Previously created paintjobs may appear shifted or skewed as a result and may need to be readjusted.

As a result of significant architectural changes between updates, previous Theater files can no longer be viewed. While this is an unfortunate side effect of live game development, we will make every effort to keep instances of incompatibility to an absolute minimum.
General stability improvements across Multiplayer, Blackout, and Zombies.

Multiplayer

General

Improved spawn points on various maps in Free For All and Domination.

Added ?Sprint Cancels Reload? to Options in the Controls category. When enabled, this allows players to cancel their weapon reload by starting a sprint. This will not prevent sprinting or reloading if players are already sprinting and perform a reload.

Addressed several issues with mantling and other first-person combat animations.

Specialists

Fixed an exploit ...