JAK1 and rheumatoid arthritis: Currently, there is a paucity of approved disease‐modifying drugs specifically for improving OA outcomes.[7a] However, JAKi, such as tofacitinib, is clinically used to treat rheumatoid arthritis (RA) by effectively reducing synovial inflammation and preventing RA‐induced cartilage erosion.[20] In human degenerated cartilage, the number of p‐JAK1 and p‐JAK3 positive cells was significantly increased compared to relatively healthy cartilage (Figure S10, Supporting Information).