CASP5 and pancreatic adenocarcinoma: Increasing evidence has shown that patients with high TMB may benefit from immunotherapy, which indicates that CASP3, CASP5, CASP6, CASP8, IL18, and PYCARD genes have the potential to be used as biomarkers for predicting immunotherapy in patients with PAAD and may provide a new perspective for the development of PAAD treatment.