Pruritic rash is associated with ICI-based therapy [320,321], with the highest occurrence manifesting in response to anti-CTLA-4 inhibitors alone or in combination with an anti-PD-1 inhibitor [213,322,323], While pruritus is usually associated with the development of other skin diseases, its development in cancer patients can occur independently from cutaneous alterations [324,325,326], either as a direct or indirect side effect of ICIs. The gene discussed is PDCD1; the disease is cancer.