Anti PD-1 Plus Postbiotic Versus Anti PD-1 Alone in Locally Advanced or Metastatic, Treatment naïve, Cutaneous Melanoma Study

Inclusion Criteria: * Patients 18 years or older * Histologically confirmed, unresectable stage IIIC or IV metastatic melanoma; * Eastern Cooperative Oncology Group performance status of 0 or 1; * The patient must treatment naïve for metastatic disease * Patients who have received anti-PD-1 therapy or anti BRAF/MEK in adjuvant setting and relapsed after 6 months of ending adjuvant therapy are allowed to enter clinical study. * Patient has at least one measurable lesion that qualifies as a target lesion based on RECIST 1.1. Tumor lesions situated in a previously irradiated area, or in an area subjected to other loco-regional therapy, are not considered measurable unless there has been demonstrated progression in the lesion. * Patient is willing to undergo a pretreatment tumor biopsy or provide qualifying archival tumor tissue. To qualify, archival tissue must have been sampled after last exposure to any systemic anti-neoplastic agent (including TVEC or anti-PD-L1 therapy whichever is last). Patients unable to undergo a biopsy may be enrolled if risk/benefit ratio of biopsy is considered unfavorable and/or when a biopsy would likely lead to significant delays in care. This decision must be accompanied by supporting documentation from the Investigator and performed in consultation with Medical Monitor. All pretreatment tissue must have been collected no more than 120 days prior to screening. * Patient has recovered from the effects of any previous chemotherapy, immunotherapy, other prior systemic anticancer therapy, radiotherapy, and/or surgery (ie, residual toxicity no worse than Grade 1 \[Grade 2 treatment-associated peripheral neuropathy and/or any grade of alopecia are acceptable assuming all other inclusion criteria are met\]). * Patient who has received prior systemic anti-neoplastic agent(s) must wait at least 5 half-lives or 4 weeks (whichever is shorter) following prior therapy before enrollment into the study, or 4 weeks if the half-life of a given investigational agent is not known. * Patient has an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1 within 5 days before the first dose of study drug and an estimated life expectancy of at least 3 months. * Patient has adequate hematologic reserve as evidenced by: Absolute neutrophil count (ANC) of ≥1000/μL, Absolute lymphocyte count of ≥500/μL, Platelet count of ≥75,000/μL, and Hemoglobin of ≥9 g/dL (patients may be transfused to this level, if necessary, but transfusion must occur \>1 week prior to the first dose of study drug). * Patient has adequate hepatic function as evidenced by aspartate transaminase and alanine transaminase values ≤3 × the upper limit of normal (ULN) and serum total bilirubin values of ≤1.5 × ULN (≤2 × ULN for patients with known Gilbert's syndrome) for the reference laboratory measured within 7 days prior to the first dose of study drug. For patients with documented baseline liver metastasis, the following limits will apply: 5 × ULN for transaminase and 2 × ULN for bilirubin. * Patient has adequate renal function as evidenced by a serum creatinine ≤1.5 × the ULN for the reference laboratory or a calculated creatinine clearance of ≥45 mL/min by the Cockcroft-Gault Equation measured within 7 days prior to the first dose of study drug. * Patient has international normalized ratio (INR) AND/OR prothrombin time (PT) AND activated partial thromboplastin time (aPTT) ≤1.5 × ULN unless the patient is receiving anticoagulant therapy, in which case INR and/or PT and aPTT must be within the desired therapeutic range of intended use for such anticoagulants. * Patient agrees to abide by the contraceptive requirements detailed in the protocol. * Women of childbearing potential (WOCBP) must have a negative pregnancy test (serum or urine) within 3 days before the first dose of study drug (see the protocol for the definition of WOCBP). * Life expectancy more than 3 months * Presence of instrumentally or clinically measurable or evaluable lesions Informed consent obtained Exclusion Criteria: * Patients with mucosal or with a primary ocular melanoma * Active symptomatic or asymptomatic brain metastases * Patients with the following disorders: active, known, or suspected autoimmune disease (except for some non-serious disorders, such as vitiligo and type 1 diabetes mellitus, as specified in the study protocol); * Previous malignancies (exceptions skin basocellular or squamocellular carcinoma radically resected, in situ uterine cervix in situ carcinoma radically resected) in the previous 2 years.