Inclusion Criteria:

          -  Patients with locally advanced histopathologically confirmed HNSCC not candidate for
             primary surgical treatment

          -  No distant metastasis (M0)

          -  Tumor tissue available for central testing Patient with HPV/p16 negative disease (≤70%
             positively stained cells) as determined by central testing

          -  Adequate normal organ and marrow function

          -  Measurable tumor according to RECIST

          -  Patients must be expected to complete the treatment.

          -  Age > 18 years at time of study entry

          -  Female patients must either be of non-reproductive potential or must have a negative
             serum pregnancy test upon study entry and be willing to use adequate contraceptive
             measurements as described in the protocol

          -  Non-sterilized males who are sexually active with a female partner of childbearing
             potential must be willing to use adequate contraceptive measurements as described in
             the protocol section 6.5.4

        Exclusion Criteria:

          -  Participation in another clinical study with an investigational product during the
             last 3 months

          -  Prior or current anticancer treatment to the head and neck area (e.g. radical
             attempted or tumor reductive surgery, neo-adjuvant chemotherapy, EGFR inhibitors or
             radiotherapy).

          -  Any previous treatment with a PD1 or PD-L1 inhibitor, including durvalumab or an
             anti-CTLA4, including tremelimumab

          -  Active or prior documented autoimmune or inflammatory disorders (including
             inflammatory bowel disease [eg, colitis or Crohn's disease], diverticulitis [with the
             exception of diverticulosis], systemic lupus erythematosus, Sarcoidosis syndrome, or
             Wegener syndrome [granulomatosis with polyangiitis, Graves' disease, rheumatoid
             arthritis, hypophysitis, uveitis, etc]). The following are exceptions to this
             criterion:

               -  Patients with vitiligo or alopecia

               -  Patients with hypothyroidism (eg, following Hashimoto syndrome) stable on hormone
                  replacement

               -  Any chronic skin condition that does not require systemic therapy

               -  Patients without active disease in the last 5 years may be included but only
                  after consultation with the study physician

               -  Patients with celiac disease controlled by diet alone History of primary
                  immunodeficiency

          -  History of allogeneic organ transplant

          -  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 IP 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

          -  History of hypersensitivity to durvalumab and/or tremelimumab or any excipient

          -  Uncontrolled intercurrent illness, including but not limited to, ongoing or active
             infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable
             angina pectoris, cardiac arrhythmia, interstitial lung disease, serious chronic
             gastrointestinal conditions associated with diarrhea, or psychiatric illness/social
             situations that would limit compliance with study requirement, substantially increase
             risk of incurring AEs or compromise the ability of the patient to give written
             informed consent

          -  Active infection including tuberculosis (clinical evaluation that includes clinical
             history, physical examination and radiographic findings, and TB testing in line with
             local practice), hepatitis B (known positive HBV surface antigen (HBsAg) result),
             hepatitis C, or human immunodeficiency virus (positive HIV 1/2 antibodies). Patients
             with a past or resolved HBV infection (defined as the presence of hepatitis B core
             antibody [anti-HBc] and absence of HBsAg) are eligible. Patients positive for
             hepatitis C (HCV) antibody are eligible only if polymerase chain reaction is negative
             for HCV RNA.

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

          -  Female patients who are pregnant or breastfeeding or male or female patients of
             reproductive potential who are not willing to employ effective birth control as
             described in the protocol from screening to 180 days after the last dose of durvalumab
             + tremelimumab combination therapy or 90 days after the last dose of durvalumab
             monotherapy, whichever is the longer time period

          -  Distant metastasis

          -  Patients who are institutionalised by official order

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

          -  Receipt of live attenuated vaccination within 30 days prior to study entry step 2 or
             within 30 days of receiving durvalumab or tremelimumab