Whilst irAEs seem to correlate with OS, depending on their number and severity, which organ system is affected, treatment (anti-PD1 monotherapy versus combined anti-PD1 and anti-CTLA4 treatment) and tumour type, this study only examined PFS and was not large enough to provide conclusive data on the effects of irAEs on OS. This evidence concerns the gene CTLA4 and neoplasm.