From PSU: “Turtle Rocks Back 4 Blood has just released a brand new trailer, which goes in-depth on the games card customisation system.
This customisation system allows you to enhance and change your experience each time your play, making each mission feel unique and different. The card system allows you to craft a deck of cards that you can then pick from while you play, providing you with benefits like additional grenades, better accuracy, or buffs to your character.”
Source: N4G PC Back 4 Blood Debuts Its Unique Card Customisation System In New Trailer