IL1RL1 and Skeletal muscle atrophy: In conclusion, impaired muscle regeneration results in muscle atrophy and decline in exercise capacity, this study underscored the critical role of muscle‐resident cells in inflammation and muscle regeneration, and found that the IL‐33/IL1RL1 axis plays a crucial role in activating FAPs to recruit pro‐regenerative inflammatory cells, which will provide a new therapeutic target for skeletal muscle atrophy caused by aging or other diseases.