Inclusion Criteria:  Provide a signed written informed consent for the trial Have measurable disease, per RECIST v1.1 Have a predicted life expectancy of ≥ 16 weeks Have an Eastern Cooperative Oncology Group (ECOG) performance status of Grade 0 or 1. Have adequate organ functions Part 1 : Have histologically or cytologically confirmed advanced or metastatic solid tumor for whom no standard treatment with survival benefit is available Part 2 (lung cancer, H&N) Are eligible to receive pembrolizumab monotherapy in first line (1L) metastatic setting, as standard of care and according to local treatment guidelines. Part 2 (lung cancer, H&N) : PD-L1 status positive Part 2 (melanoma) : progressed on treatment with an anti-PD-(L)1 monoclonal antibody (mAb)  Exclusion Criteria:  Have received any anti-cancer therapy within 4 weeks prior to the first dose Have received a live vaccine within 30 days prior to the first dose Have known primary CNS cancer. Have known CNS metastases unless previously treated and well controlled for at least 1 month Have concomitant second malignancies unless a complete remission was achieved at least 2 years before study entry Have a history of Grade ≥ 2 pneumonitis, active autoimmune disease, or persistent immune-mediated toxicity caused by immune checkpoint inhibitor therapy of Grade ≥ 2 Have toxicity (except for alopecia) related to prior anti-cancer therapy and/or surgery unless the toxicity is either resolved, returned to baseline or Grade 1, or deemed irreversible.Have uncontrolled or significant cardiovascular disease Part 1 : major surgery within 5 weeks before initiating treatment Part 1 : Have received prior radiotherapy within 2 weeks of start of study treatment Part 2 (lung cancer, H&N) :Have confirmation that epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), reactive oxygen species (ROS1) or any other genomic aberration approved directed therapy is indicated as primary therapy.