https://wccftech.com/sekiro-online-mod-pvp-coop/

A brand-new Sekiro mod has been released which adds unofficial PvP and co-operative play to the game on PC.

Sekiro: Shadows Die Twice lacks multiplayer a multiplayer mode, but as covered earlier this month, a PC multiplayer mod will change this. Created by modder ‘LukeYui’, this modification has now been released to the public, albeit its still in its early beta phase.