Overall, ICIs with anti-PD-1 or anti-PD-L1 antibodies administered after the failure of standard chemotherapy are effective, with a clinical response in approximately 20% of cases; however, the treatment is associated with an enhanced risk of severe irAES, especially in the case of thymoma (up to 70% of G ≥ 3 irAEs), despite the exclusion in these trials of patients with active autoimmune disease. This evidence concerns the gene PDCD1 and thymoma.