Purgatory Walkers Cong Gu Huo Niao Kaishi: Long Cheng Fengyun

Li Yan, a martial artist with extraordinary talent, has only a few months left to live due to a terminal illness. When he was in a desperate situation, he accidentally met a man who called himself "Tapir" and was sent into a fruit of the "Yanfu Fruit Tree". Li Yan must complete three tasks issued by the system within the time limit, and earn money through boxing matches in exchange for Yanfu points to buy medicine that can cure terminal illnesses. As he gets to know Longyuan Fortress where he is located, Li Yan is gradually involved in the disputes in the fortress, and he also realizes that there are other Yanfu Walkers competing with him in secret. After overcoming many difficulties, Li Yan finally successfully completed the task and gained a new life. (Source: bilibili, translated)