PEnile Cancer Radio- and Immunotherapy CLinical Exploration Study

Inclusion Criteria: * Written informed consent, prior to performing any protocol-related procedures, including screening evaluations. * Age \> 18 years at time of study entry. * Advanced histologically documented, squamous cell carcinoma of the penis or distal urethra. Advanced disease is defined as: * Distant metastases, OR * LRAPC, defined as a large or inoperable primary tumor (T4), palpable nodes \>3cm in diameter or fixed nodes, suspicion of extra-nodal extension or pelvic node involvement (N2/N3) * Arm A: Locoregional disease (with or without distant metastases), likely to derive benefit from locoregional radiotherapy and not previously treated with radiotherapy. * Arm B: Benefit of locoregional radiotherapy unlikely OR previously treated with irradiation. * World Health Organisation (WHO) performance status of 0 or 1. * Life expectancy of \> 12 weeks. * Adequate normal organ and marrow function as defined below: * Haemoglobin ≥ 5.6/mmol/L * White blood cell count (WBC) ≥ 2 x 109/L * Absolute neutrophil count (ANC) ≥ 1.5 x 109/L * 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, who will be allowed in consultation with a study physician. * AST/ALT ≤ 2.5 x institutional ULN unless liver metastases are present, in which case it must be ≤ 5x ULN. * Serum creatinine clearance \>30 mL/min by calculation with the Cockcroft-Gault formula (Cockcroft and Gault 1976) or by 24-hour urine collection measurement. Exclusion Criteria: * Involvement in the planning and/or conduct of the study (applies to both Roche staff and/or staff at the study site) or previous enrolment in the present study. * Participation in another clinical study with an investigational product during the last 4 weeks * Any previous treatment with a PD-1 or PD-L1 inhibitor * History of another primary malignancy except for: * Malignancy treated with curative intent and with no known active disease ≥2 years before the first dose of study drug * Low potential risk of 3-year cancer-specific death (estimated\<5%), including adequately treated non-melanoma skin cancer without evidence of disease, adequately treated carcinoma in situ without evidence of disease, or localized prostate cancer treated with curative intent and absence of prostate-specific antigen (PSA) relapse or incidental prostate cancer (Gleason score ≤ 7 and PSA \< 10 ng/mL) undergoing active surveillance. * Treatment with the last dose of any systemic anti-cancer therapy ≤ 21 days prior to the first dose of study drug. Local treatment of isolated lesions for palliative intent is acceptable (eg, local surgery or radiotherapy). * Current or prior use of immunosuppressive medication within 14 days before the first dose of study drug, with the exceptions of intranasal and inhaled corticosteroids or systemic corticosteroids at doses ≤10 mg/day of prednisone, or an equivalent corticosteroid. * History of primary immunodeficiency, allogeneic organ transplant or autoimmune disease, including - but not limited to - myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, vascular thrombosis associated with antiphospholipid syndrome, Wegener's granulomatosis, Sjögren's syndrome, Guillain-Barré syndrome, multiple sclerosis, vasculitis, or glomerulonephritis. Patients with a history of autoimmune-related hypothyroidism on a stable dose of thyroid replacement hormone will not be excluded from this study. Patients with controlled diabetes mellitus type I on a stable dose of insulin regimen may be eligible for this study. * Uncontrolled significant intercurrent illness, including - but not limited to - ongoing or active infection (including acute or chronic hepatitis B, hepatitis C or human immunodeficiency virus (HIV)), symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, active peptic ulcer disease or gastritis, active bleeding diatheses 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 active tuberculosis * Any condition that, in the opinion of the investigator, would interfere with evaluation of study treatment or interpretation of patient safety or study results * Brain metastases or leptomeningeal disease. Inclusion of patients with brain metastases is allowed if patients have been adequately treated, are not symptomatic and show no signs of progression on brain imaging 28 days after completion of treatment (including surgery, radiotherapy or treatment with systemic corticosteroids). * Subjects with uncontrolled seizures.