Inclusion Criteria:  Histologically confirmed soft-tissue sarcoma with unknown translocation (including the following histologies but not limited to undifferentiated pleomorphic sarcomas, dedifferentiated liposaromas or leiomyosarcomas). Diagnosis must be reviewed or confirmed by the RRePS Network (Réseau de référence en pathologie des sarcomes et des viscères) as recommended by the French NCI (Institut National du Cancer, Inca). Metastatic or unresectable locally advanced disease, No previous systemic treatment for advanced/metastatic disease, For TLS status: available archived FFPE (Formalin-Fixed Paraffin-Embedded) tumor tissue sample or tumor material newly obtained by biopsy. Except if TLS analysis have been already performed by Biopathological platform at Bergonié Institute, presence or absence of TLS should be confirmed by central review based on FFPE tumor tissue sample (archived or newly obtained by biopsy for research purpose), Age ≥ 18 years, ECOG ≤ 1, Life expectancy > 3 months, Patients must have measurable disease defined as per RECIST v1.1 with at least one lesion that can be measured in at least one dimension as > 10 mm with spiral CT scan., Patient must comply with the collection of tumor biopsies and biomarkers study. Tumors must be accessible for biopsy, Adequate hematological, renal, metabolic and hepatic function Female subjects of childbearing potential must have a negative serum pregnancy test within 7 days prior to randomization. Serum or urine pregnancy test must be repeated within 72 hours prior to receiving the first dose of study medication, Both women and men must agree to use a highly effective method of contraception throughout the treatment period and for at least two months after discontinuation of treatment for women and four months for men. No prior or concurrent malignant disease diagnosed or treated in the last 3 years except for superficial/non-invasive bladder cancer, or basal or squamous cell carcinoma in situ treated with curative intent; b. endoscopically resected GI cancers limited to the mucosal layer without recurrence in > 1 year, Recovery to grade ≤ 1 from any adverse event derived from previous treatment (excluding alopecia and vitiligo of any grade and non-painful peripheral neuropathy grade ≤ 2) according to to NCI-CTCAE, version 5.0, Voluntarily signed and dated written informed consent prior to any study specific procedure, Patients with a social security in compliance with the French law.  Exclusion Criteria:  Previous treatment with doxorubicin, daunorubicin, epirubicin, idarubicin and/or any other anthracyclines or anthracediones at the maximum cumulative dose or any approved or investigational treatment targeting PD1, PD-L1 or TGFB1, Known central nervous system malignancy (CNS), Men or women of childbearing potential who are not using an effective method of contraception as previously described; women who are pregnant or breast feeding, Participation to a study involving a medical or therapeutic intervention in the last 30 days, Previous enrolment in the present study, Patient unable to follow and comply with the study procedures because of any geographical, social or psychological reasons, Known hypersensitivity to any involved study drug or any of its formulation components, Any history of anaphylaxis, or recent, within 5 months, history of uncontrollable asthma, Individuals deprived of liberty or placed under legal guardianship,  Any of the following cardiac criteria:  Mean resting corrected QT interval (QTcF) ≥ 470 msec, obtained from three consecutive ECGs, Any clinically important abnormalities in rhythm, conduction or morphology of resting ECG, LVEF ≤ 50% per CTCAE v5 by MUGA or echocardiogram Any factors increasing the risk of QTc prolongation or arrhythmic events such as heart failure, hypokalaemia, potential for torsades de pointes, congenital long QT syndrome, family history of long QT syndrome or unexplained sudden death under 40 years old or any concomitant medication known to prolong the QT interval, Experience of any of the following procedures or conditions in the preceding 6 months: coronary artery bypass graft, angioplasty, vascular stent, myocardial infarction, unstable angina pectoris, uncontrolled hypertension, congestive heart failure NYHA Grade ≥2, ventricular arrhythmias requiring continuous therapy, supraventricular arrhythmias including atrial fibrillation, which are uncontrolled, haemorrhagic or thrombotic stroke, including transient ischaemic attacks, cerebral vascular accident/stroke or any other central nervous system bleeding Active autoimmune disease that might deteriorate when receiving an immunostimulatory agent: History of bleeding diathesis or recent major bleeding event , Prior organ transplantation including allogenic stem-cell transplantation, except transplants that do not require immunosuppression, Uncontrolled intercurrent illness, including but not limited to, ongoing or active infection requiring systemic therapy, drug-induced interstitial lung disease or subject has had a history of drug-induced pneumonitis that has required oral or IV steroids, and/or other diseases, which in the opinion of the investigator might impair the subject's tolerance for the study or ability to consistently participate in study procedures, Active infection including tuberculosis , Has known active hepatitis B or hepatitis C, Has a known history of Human Immunodeficiency Virus infection, Receipt of live attenuated vaccine within 30 days prior to the first dose of treatment. Note: Patients, if enrolled, should not receive live vaccine within 30 days prior to the first dose of treatment, whilst receiving study treatments and up to 30 days after the last dose. Seasonal flu vaccines that do not contain a live virus are permitted, Patients with current or history of deep vein thrombosis within 6 months prior to randomization, Any contraindication to biopsy for the research, Any other contraindication to Doxorubicin administration,. Patients with oral anticoagulation therapy based on Vitamin K antagonist. Prior mediastinal radiation.