PDCD1 and familial pancreatic carcinoma: An increase in CTLA4 and PD-1 expression was seen in the low-risk group, and anti-PD-1/PD-L1 antibodies were less effective against pancreatic cancer than they were against melanoma, renal cell carcinoma, and non-small cell lung cancer, owing to immunostasis or drug resistance [74,75,76].