Inclusion Criteria:  Investigators must ensure that patients are able to understand the requirements of the study and provide informed consent Age ≥18 years Histological or cytological diagnosis of pancreatic adenocarcinoma Stage IV disease No prior treatment for advanced disease. Patients who have received chemotherapy for localize disease are eligible if at least six months have elapsed from the last chemotherapy treatment Measurable disease per RECIST 1.1 as determined by the investigator ECOG (Eastern Cooperative Oncology Group) PS 0-1  Sufficient hematopoietic, renal and liver function as defined as:  Neutrophil count ≥ 1.5 x 10*9 / L Platelet count ≥ 100 x 10*9 / L Bilirubin ≤ 1.5 x ULN (upper limit of normal) AST and / or ALT ≤2.5 x ULN or ≤5 for patients with liver disease Serum creatinine ≤ 1.5 x ULN Tumor lesion amenable for safe repeated biopsy  Women of child-bearing age and men who wish to participate in the study must agree to use appropriate contraceptive methods from the signing of informed consent until 3 months after discontinuation of the study drug  Adequate contraception includes abstinence, oral contraceptives, transdermal patches, and injections that prolong release of a progestogen (starting at least 4 weeks prior to the administration of the investigational drug), double barrier method: condom or female condom (diaphragm or condom / vaginal) plus spermicide, intrauterine device (IUD), implant or a vaginal ring (placed at least 4 weeks prior to administration of investigational drug) or male partner sterilization (vasectomy with documentation of azoospermia) before the inclusion of the woman in the trial if the male is the only sex partner of the woman  Investigators must ensure that patients recruited will be able to meet all study requirements, including tumor biopsy, chemotherapy and monitoring  Exclusion Criteria:  Active or uncontrolled infection, disease or serious medical condition that may interfere with the patient's eligibility or treatment History of psychiatric condition that would compromise the patient's ability to understand or comply with the requirements of the protocol, or the ability to provide informed consent Concurrent antineoplastic therapy Pregnant or lactating women History of allergic reactions attributed to compounds of similar chemical structure or similar biological study drug composition History of life-threatening serious adverse events to Gemcitabine or Nab-Paclitaxel Prior chemotherapy or chemo-radiation therapy for advanced pancreatic cancer Patients requiring or being treated with potent CYP3A4 inhibitors and inducers Other malignancies treated within the last 5 years, except in situ cervix carcinoma or nonmelanoma skin cancer History of interstitial lung disease Subjects with a history or presence of a known clotting disorder or difficulty achieving haemostasis will be excluded  Primary or secondary immunodeficiency, including immunosuppressive disease or autoimmune disease (including autoimmune endocrinopathies).  Note: Subjects with diabetes type 1, vitiligo, psoriasis, hypo-, or hyperthyroid disease not requiring immunosuppressive treatment are eligible. Subjects with Type 2 diabetes mellitus are allowed  Subjects with a known history of human immunodeficiency virus 1 and 2, human T lymphotropic virus 1.  Administration of anticancer medications or investigational drugs within the following intervals before the first administration of study drug:  A 1-week washout is permitted for palliative radiation to non- central nervous system (CNS) disease, with medical monitor approval. Subjects must also not have had radiation pneumonitis as a result of treatment and cannot participate in the study if they are on chronic corticosteroids for radiation pneumonitis Note: Bisphosphonates and denosumab are permitted medications  ≤7 days for prior corticosteroid treatment, with the following exceptions:  Use of an inhaled or topical corticosteroid is permitted Corticosteroid premedication for radiographic imaging for dye allergies is permitted Use of physiologic corticosteroid replacement therapy may be approved after consultation with the medical monitor ≤7 days for immunosuppressive-based treatment for any reason, with the exceptions noted above for prior corticosteroid treatment ≤21 days or 5 half-lives before first dose of study treatment for all other investigational study drugs or devices. For investigational agents with long half-lives (e.g., >5 days), enrollment before the fifth half-life requires medical monitor approval Has not recovered to grade ≤1 from toxic effects of prior therapy and/or complications from prior surgical intervention before starting therapy Note: Subjects with grade ≤2 neuropathy and alopecia are an exception and may enroll History or presence of an abnormal ECG that, in the investigator's opinion, is clinically meaningful Concurrent participation in other investigational drug trials  Known central nervous system (CNS) involvement as follows:  Untreated CNS metastases. Leptomeningeal metastases. Note: Patients may be eligible if CNS metastases have been treated and patients have neurologically returned to baseline (except for residual signs and symptoms related to the CNS treatment).