There is no consensus on the best method for distinguishing the cause of elevated liver enzymes in patients being treated with ICPi's when combined with various chemotherapies. Important considerations include time of onset, severity, and presence of hepatobiliary metastases. Hepatotoxicity from ICP...

I would add that the patient context is always key to such a question. Does the patient have any hepatic disease that would be worsened by either chemo or immune-checkpoint inhibitor (ICI) therapy? What chemo drugs are being used and do they have a significant probability of ↑ LFTs?  And, ...