Inclusion Criteria:  I1. Adult male or female patient with confirmed diagnosis of advanced/metastatic cancer to be treated with standard anti-cancer treatment according to :  For metastatic Small cell lung cancer (SLCC) : treatment by Immunotherapy ± chemotherapy For Recurrent/Metastatic Head and Neck squamous cell carcinoma (HNSCC) : treatment by Immunotherapy (all lines) For Metastatic Urothelial carcinoma : treatment by 1st line chemotherapy with avelumab as maintenance treatment (patients will be enrolled following 4 to 6 cycles of CT, only patient initiating avelumab maintenance are eligible (i.e. patients with SD or PR after CT) For MSI-High, any tumor types : treatment by Immunotherapy For HPV-related cancers, any tumor types : treatment by Immunotherapy Metastatic GIST : treatment by Imatinib BRAF- V600E tumors (lung and thyroid cancer) : treatment by Dabrafenib + trametinib BRAF- V600E tumors (CRC cancer) : treatment by Encorafenib + cetuximab All solid tumor types with ret fusion / mutation : treatment by Selpercatinib Metastatic Triple negative breast cancer (TNBC) : treatment by 1st line chemotherapy Glioblastoma : treatment by Radiochemotherapy Advanced high grade epithelial ovarian cancer : treatment by 1st line Chemotherapy Chronic Lymphocytic Leukemia (CLL) in the relapsed setting : treatment by Bruton Kinase Inhibitors  I2. All solid tumor cohorts: Availability of an archival representative formalin-fixed paraffin-embedded (FFPE) tumor sample [...]  I3. All solid tumor cohorts: Disease evaluable as per RECIST V1.1  I4. All solid tumor cohorts excluding Glioblastoma: Tumor lesion visible by medical imaging and accessible to repeatable percutaneous or endoscopic mandatory de novo tumor sampling [...]  I5. Performance status (PS) ECOG 0 or 1.  I6. Patient should understand, sign, and date the written ICF prior to any protocol-specific procedures performed. Patient should be able and willing to comply with study visits and procedures including sequential tumor biopsies as per protocol.  I7. Patient must be covered by a medical insurance.  Exclusion Criteria:  NI1. All solid tumor cohorts - Patient with non-acceptable tumor sample at screening.  NI2. Any condition contraindicated with blood/tumor sampling procedures required by the protocol.  NI3. Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure.  NI4. Pregnant or breast-feeding woman.