Warhorse Studios released a small but intriguing update 1.5.5 for Kingdom Come: Deliverance II — the studio's first collaboration, and with Paradox Interactive's Crusader Kings III no less.
The game adds a book called "Three Crusader Kings": copies are hidden in various spots around Troskowitz and Kuttenberg — a great excuse to set off exploring Bohemia again.
The exchange is mutual: Crusader Kings III, in turn, received themed add-ons inspired by KCD2. The studios marked the event with joint streams.