Classical “spontaneous” PNS typically arise in patients with cancer who have never received ICIs, while PD-1/PD-L1 inhibitor–related PNS (PNS-ICI) represent either de novo induction or unmasking/exacerbation of pre-existing paraneoplastic autoimmunity under checkpoint blockade (23–26). The gene discussed is CD274; the disease is paraneoplastic neurologic syndrome.