ICI-induced inflammatory arthritis presents as inflammatory joint pain, swelling, and stiffness, resembling autoimmune arthritis, such as RA, where the leading mechanism is the dysregulation of immune checkpoints, principally the CTLA-4 and PD-1 pathways, which act as critical regulators of T-cell activation and tolerance [87]. This evidence concerns the gene PDCD1 and rheumatoid arthritis.