PDCD1 and colitis: Camrelizumab (AiRuiKa) is a humanized high-affinity IgG 4-κ anti-PD-1 monoclonal antibody that acts by binding to and blocking the binding of PD-1 to its ligand, PD-L1.[4] However, this may lead to excessive activation of T cells, triggering T cell imbalance, which in turn leads to adverse immune responses, including immune-related reactive cutaneous capillary endothelial cell proliferation (RCCEP), colitis, arthritis, hepatitis, etc.