Study to Assess MEDI4736 With Either AZD9150 or AZD5069 in Advanced Solid Tumors & Relapsed Metastatic Squamous Cell Carcinoma of Head & Neck

Key Inclusion Criteria:

* Male and female patients must be at least 18 years of age.
* Has an Eastern Cooperative Oncology Group (ECOG) PS score of 0 or 1.
* Has measurable disease, defined as at least 1 lesion that can be accurately measured in at least 1 dimension (longest diameter to be recorded) with a minimum size of 10 mm by computerised tomography (CT) scan, except lymph nodes which must have minimum short axis size of 15 mm (CT scan slice thickness no greater than 5 mm in both cases). Indicator lesions must not have been previously treated with surgery, radiation therapy, or radiofrequency ablation unless there is documented progression after therapy.
* Has undergone ≤3 previous regimens (depending on treatment arm) of cytoreductive therapies including, but not limited to, platinum-based compounds, taxanes, or 5-fluorouracil. for B7 \& B8, no prior systemic treatments should have been received for RM SCCHN
* Adequate organ and marrow function
* Female subjects of childbearing potential and male subjects with partners of childbearing potential should ensure use of a highly effective method of birth control as defined in study protocol
* Additional inclusion for part A: Has a histological confirmation of a solid malignancy (other than HCC) that is refractory to standard therapy or for which no standard of care regimen currently exists.
* Addition inclusion for Part A (A6) Has a histological confirmation of castrate-resistant prostate cancer
* Additional inclusion for Part B:Has histologically and/or cytologically confirmed SCCHN that is RM and not amendable to curative therapy by surgery or radiation. Squamous cell carcinoma of the head and neck originating from the following sites is eligible: oral cavity, oropharynx, larynx, or hypopharynx. Has at least 1 SCCHN tumour lesion (TL) amenable to biopsy and must have failed, refused, or has been found to be ineligible for least 1 prior platinum-based chemotherapy for RM-SCCHN Additional inclusion criteria for Arms B1 \& B2: must have had prior exposure to anti PDL-1 antibody
* Arms B1-B6: Has undergone 1-3 previous regimens of cytoreductive chemo-therapies Arm B7 \& B8: with no prior exposure to anti-PD-(L)1 therapies and have received no prior systemic treatment for RM SCCHN

Key Exclusion Criteria:

\- Spinal cord compression unless asymptomatic and not requiring steroids for at least 4 weeks before the start of study treatment. - Presently has a second malignancy other than SCCHN, or history of treatment for invasive cancer other than SCCHN in the past 3 years. Exceptions are: Previously treated in-situ carcinoma (ie, noninvasive) Cervical carcinoma stage 1B or less Noninvasive basal cell and squamous cell skin carcinoma Radically treated prostate cancer (prostatectomy or radiotherapy) with normal prostate-specific antigen, and not requiring ongoing antiandrogen hormonal therapy

* Patients must have completed any previous cancer-related treatments before enrolment. Any concurrent chemotherapy \[Chemotherapy washout within 21 days or 5 half-lives (whichever is shorter) from enrolment\], radiotherapy, immunotherapy, or biologic, or hormonal therapy for cancer excludes the patient (concurrent use of hormones for noncancer-related conditions \[eg, insulin for diabetes and hormone replacement therapy\] is acceptable),
* Experiencing CTCAE grade \>1 events, experienced immune-related grade ≥3AEs with prior immunotherapy
* Has active or prior autoimmune disease within the past 2 years
* Has active or prior inflammatory bowel disease or primary immunodeficiency
* Undergone an organ transplant that requires use of immunosuppressive treatment
* Abnormalities in rhythm, conduction or morphology of resting 12-lead ECG
* uncontrolled comorbid conditions
* Received a live attenuated vaccine within 30 days of first study dose, unable to take oral medications
* History of allergic reactions to study compounds or excepients Additional exclusion criteria Part A: Patients with clinically active brain metastases and prior exposure to AZD9150, AZD5069, MEDI4736, or any other anti PD (L)1 antibody.

Additional exclusion criteria Part B: Patients with brain metastases (known or suspected) Additional exclusion criteria Part B: treatment arms B3, B4, B5, B6, B7 and B8: prior exposure to AZD9150, AZD5069, MEDI4736, or any other anti PD (L)1 antibody.