In retrospective studies, non-conclusive evidence has been collected about a possible association of the occurrence of irAEs with durable responses and survival benefit from ICIs, both for anti-CTLA4 and anti-PD1, first in advanced melanoma [10–15] and then in other tumor settings, particularly non-small cell lung cancer (NSCLC) [16–18]. Here, CTLA4 is linked to melanoma.