Among seven patients treated with nivolumab or pembrolizumab for metastatic melanoma (n = 2) or NSCLC (n = 5), affected by a chronic or past HBV/HCV infection, only one patient affected by metastatic melanoma showed an increase in alanine aminotransferase (ALT) of grade 2 according to the Common Terminology Criteria for Adverse Events (CTCAE). This evidence concerns the gene GPT and non-small cell lung carcinoma.