Inclusion Criteria:

          -  Written informed consent and any locally-required authorization (e.g., HIPAA in the
             UEU Data Privacy Directive in the EU) obtained from the subject prior to performing
             any protocol-related procedures, including screening evaluations

          -  Age ≥ 18 years at time of study entry or adult male or female (according to age of
             majority as defined as ≥18 years)

          -  Histologically confirmed recurrent or metastatic SCCHN (oral cavity, oropharynx,
             hypopharynx, or larynx) not amenable to therapy with curative intent (surgery or
             radiation therapy with or without chemotherapy). Patients who refuse radical resection
             are eligible.

          -  Tumor progression or recurrence during or after treatment with anti-PD1, anti-PDL1,
             anti-PDL2, anti-CTLA4, or other immune checkpoint inhibitor where the most recent dose
             was given within 3 months prior to study registration.

          -  Must give valid written consent to provide archival FFPE and/or newly acquired tumor
             tissue for the purpose of establishing baseline PD-L1 status as well as consent to
             provide on- and/or post-treatment tumor biopsy sample.

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at enrollment

          -  Life expectancy of > 6 months

          -  At least 1 lesion that can be accurately measured at baseline as > 10 mm in the
             longest diameter (except lymph nodes which must have a short axis >15 mm) with CT or
             MRI and that is suitable for accurate repeated measurements as per RECIST 1.1
             guidelines.

          -  Adequate normal organ and marrow function as defined below (within 28 days prior to
             study registration):

               -  Hemoglobin ≥ 9.0 g/dL

               -  Absolute neutrophil count (ANC) ≥ 1.5 x 109/L (> 1500 per mm3)

               -  Platelet count ≥ 100 x 109/L (>100,000 per mm3)

               -  Serum bilirubin ≤ 1.5 x institutional upper limit of normal (ULN). This will not
                  apply to subjects with confirmed Gilbert's syndrome (persistent or recurrent
                  hyperbilirubinemia that is predominantly unconjugated in the absence of hemolysis
                  or hepatic pathology), who will be allowed only in consultation with their
                  physician.

               -  AST (SGOT)/ALT (SGPT) ≤ 2.5 x institutional upper limit of normal unless liver
                  metastases are present, in which case it must be ≤ 5x ULN

               -  Serum creatinine level <1.5 x ULN and CL>40 mL/min by the Cockcroft-Gault formula
                  (Cockcroft and Gault 1976) or by 24-hour urine collection for determination of
                  creatinine clearance:

        Males:

        --Creatinine CL (mL/min) = Weight (kg) x (140 - Age) 72 x serum creatinine (mg/dL)

        Females:

        --Creatinine CL (mL/min) = Weight (kg) x (140 - Age) x 0.85 72 x serum creatinine (mg/dL)

          -  Female subjects must either be of non-reproductive potential (ie, post-menopausal by
             history: ≥60 years old and no menses for ≥1 year without an alternative medical cause;
             OR history of hysterectomy, OR history of bilateral tubal ligation, OR history of
             bilateral oophorectomy) or must have a negative serum pregnancy test upon study entry.

          -  Male subjects with a female partner of childbearing potential must commit to true
             abstinence from heterosexual contact or commit to the use of male condom plus
             spermicide throughout the course of the study, and avoid fathering a child during the
             course of the study (including dose interruptions) and for 6 months following the last
             dose of azacitidine.

          -  All men and women of childbearing potential must use acceptable methods of birth
             control throughout the study as described below:

        Females of childbearing potential: Recommendation is for at least one highly effective
        contraceptive methods during the study and must agree to continue using such precautions
        for 180 days after the last dose of investigational product.

        Non-sterilized males : Non-sterilized male patients who are sexually active with a female
        partner of childbearing potential must use male condom plus spermicide from screening
        through 180 days after the last dose of investigational product.

        -Subject is willing and able to comply with the protocol for the duration of the study
        including undergoing treatment and scheduled visits and examinations including follo

        Exclusion Criteria:

          -  Involvement in the planning and/or conduct of the study (applies to AstraZeneca staff
             and/or staff at the study site)

          -  Histologically confirmed squamous cell carcinoma of any other primary anatomic
             location in the head and neck (eg. paranasal cavity) and non-squamous histologies (eg.
             nasopharynx or salivary gland)

          -  History of another primary malignancy except for:

               -  Malignancy treated with curative intent and with no known active disease ≥5 years
                  before the first dose of study drug and of low potential risk for recurrence

               -  Adequately treated non-melanoma skin cancer or lentigo maligna without evidence
                  of disease

               -  Adequately treated carcinoma in situ without evidence of disease eg, cervical
                  cancer in situ

          -  Receipt of the last dose of anti-cancer therapy (chemotherapy, immunotherapy,
             endocrine therapy, targeted therapy, biologic therapy, tumor embolization, monoclonal
             antibodies, other investigational agent) ≤ 21days prior to the first dose of study
             drug

          -  Mean QT interval corrected for heart rate (QTc) ≥470 ms calculated from 3
             electrocardiograms (ECGs) using Fredericia's Correction

          -  Current or prior use of immunosuppressive medication within 28 days before the first
             dose of durvalumab (MEDI4736) or tremelimumab, with the exceptions of intranasal and
             inhaled corticosteroids or systemic corticosteroids at physiological doses, which are
             not to exceed 10 mg/day of prednisone, or an equivalent corticosteroid

          -  Any unresolved toxicity NCI CTCAE grade 2 from previous anti-cancer therapy with the
             exception of alopecia, vitiligo, and the laboratory values defined in the inclusion
             criteria.

          -  Patients with Grade > 2 neuropathy will be evaluated on a case-by-case basis and may
             be included after consultation with the Study Physician.

             --Patients with irreversible toxicity not reasonably expected to be exacerbated by
             treatment with their assigned IP (eg, hearing loss) may be included after consultation
             with the Study Physician.

          -  Any prior Grade ≥3 immune-related adverse event (irAE) while receiving any previous
             immunotherapy agent, or any unresolved irAE >Grade 1

          -  Abnormal coagulation parameters (PT >15 seconds, PTT>40 seconds, and/or INR >1.5)

          -  Active or prior documented autoimmune disease within the past 2 years NOTE: Subjects
             with vitiligo, Grave's disease, or psoriasis not requiring systemic treatment (within
             the past 2 years) are not excluded.

          -  Active or prior documented inflammatory bowel disease (e.g., Crohn's disease,
             ulcerative colitis)

          -  History of primary immunodeficiency

          -  History of allogeneic organ transplant

          -  History of hypersensitivity to durvalumab (MEDI4736), tremelimumab, or any excipient

          -  Known or suspected hypersensitivity to azacitidine or mannitol

          -  Uncontrolled intercurrent illness including, but not limited to, ongoing or active
             infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable
             angina pectoris, cardiac arrhythmia, myocardial infarction in the past 6 months,
             active peptic ulcer disease or gastritis, active bleeding diatheses including any
             subject known to have evidence of acute or chronic hepatitis B, hepatitis C or human
             immunodeficiency virus (HIV), or psychiatric illness/social situations that would
             limit compliance with study requirements or compromise the ability of the subject to
             give written informed consent

          -  Known history of previous clinical diagnosis of tuberculosis

          -  Uncontrolled systemic fungal, bacterial or viral infection (defined as ongoing
             signs/symptoms related to the infection without improvement despite appropriate
             antibiotics, antiviral therapy and/or other treatment)

          -  History of leptomeningeal carcinomatosis

          -  Receipt of live attenuated vaccination within 30 days prior to study entry or within
             30 days of receiving durvalumab (MEDI4736) or tremelimumab

          -  Female subjects who are pregnant, breast-feeding or male or female patients of
             reproductive potential who are not employing an effective method of birth control

          -  Any condition that, in the opinion of the investigator, would interfere with
             evaluation of study treatment or interpretation of patient safety or study results

          -  Symptomatic or uncontrolled brain metastases requiring concurrent treatment, inclusive
             of but not limited to surgery, radiation and/or corticosteroids.

          -  Subjects with uncontrolled seizures.

          -  Female patients who are pregnant or breastfeeding or male or female patients of
             reproductive potential who are not willing to employ effective birth control from
             screening to 180 days after the last dose of azacitidine, durvalumab (MEDI4736) and/or
             tremelimumab therapy. Lactating females must agree not to breast feed throughout this
             period