Deck-building games have emerged as competitive counterparts to collectible card games. The basic premise is to use cards as “currency” to buy and build a deck that is used in play. In Pathogenesis, a deck-building game released in 2017, players assemble microbial pathogens and add virulence factors and microbial defense mechanisms through play to attack human body barrier defenses in tissue, respiratory, and gastrointestinal tracts. As the attacks proceed and players breach the barrier defenses, the body fights back using adaptive and innate immune responses like inflammation, complement, and T cells represented in cards that players also accumulate. Players win when they defeat the tracts’ immune responses (pathogen, virulence, and microbial defense cards overwhelm barrier defense and immune cards) and lose if game play takes too long and physiologic immunity develops.