Endoscopic Ultrasound Radiofrequency Ablation and Immunotherapy Pembrolizumab for Locally Advanced Unresectable and Metastatic Pancreatic Duct Adenocarcinoma

Participant will undergo 8 weeks of NAC (treating physician's choice). Possible regimens are either mFOLFIRINOX or NALIRIFOX or Gemcitabine Nab-Paclitaxel ± Cisplatin (GA+/-Cisplatin) or Capecitabine (Xeloda).

2-12 weeks after initial chemotherapy and after the first EUS-RFA treatment, patients will receive 400 mg every 6 weeks of pembrolizumab via infusion. Participants will be administered standard of care chemotherapy and pembrolizumab every 6 weeks.

After 2-12 weeks of chemotherapy, patients will undergo EUS-RFA treatment 1 session every 6 weeks. Each RFA treatment will be for up to 5 cycles at 30W for 20 seconds or until there is an increase in measured impedance. After the 5th EUS-RFA, if there is clinical benefit, then patients will continue with EUS-RFA treatments until no active tumor is seen. During each session, the therapeutic gastroenterologist will evaluate if there is any tumor to undergo RFA. If no active tumor seen, then will abort RFA