Key Inclusion Criteria:  Asian race and Japanese ethnicity Have a histologically or cytologically confirmed non-CNS solid tumor that is metastatic or unresectable and for whom there is no available standard therapy Have measurable disease according to RECIST 1.1 Have Eastern Cooperative Oncology Group (ECOG) 0-1 Have an acceptable hematological status Have acceptable liver function Have an acceptable coagulation status Have acceptable renal function  Key Exclusion Criteria:  Have uncontrolled intercurrent illness, including but not limited to:  Ongoing or active infection requiring intravenous treatment with anti-infective therapy Symptomatic congestive heart failure (Grade III or IV as classified by the New York Heart Association), unstable angina pectoris or cardiac arrhythmia Uncontrolled hypertension defined as systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 100 mmHg, despite optimal medical management Ongoing or recent evidence of autoimmune disease History of irAEs that led to prior checkpoint treatment discontinuation Prior history of myositis, Guillain-Barré syndrome, or myasthenia gravis of any grade History of chronic liver disease or evidence of hepatic cirrhosis History of non-infectious pneumonitis that has required steroids or currently has pneumonitis History of organ allograft (except for corneal transplant) or autologous or allogeneic bone marrow transplant, or stem cell rescue within 3 months prior to the first dose of GEN1046 Serious, non-healing wound, skin ulcer (of any grade), or bone fracture Any history of intracerebral arteriovenous malformation, cerebral aneurysm, new (younger than 6 months) or progressive brain metastases or stroke  Prior therapy:  Radiotherapy: Radiotherapy within 14 days prior to first GEN1046 administration. Palliative radiotherapy will be allowed. Treatment with an anti-cancer agent (within 28 days or after at least 5 half-lives of the drug, whichever is shorter), prior to GEN1046 administration. Accepted exceptions are bisphosphonates (e.g., pamidronate, zoledronic acid, etc.) and denosumab Toxicities from previous anti-cancer therapies that have not adequately resolved