I believe your doctor would like you to take aggressive chemo because there is an increase in liver mets on your PET. Meaning your current treatment or remission has ended. None of us are ever ready for this, even though we know it happens. It is a difficult thing to come to terms with.
“Multiple new diffuse hypermetabolic hepatic metastases“ loosely translates to multiple new liver mets.
Taking aggressive chemo no doubt feels like a step back, but sometimes a detour to more aggressive treatment can shrink things down to allow you to return to less aggressive treatments. I understand wanting another immunotherapy over chemo for sure. Have you discussed this with your doctor?
Has your doctor discussed this PET scan with you?