An Open-label, Phase I/II First in Human, Dose Escalation, Optimisation and Expansion Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, Immunogenicity and Anti-tumour Activity of IPN01203 in Participants With Locally Advanced or Metastatic Solid Tumours Who Have Progressed on or After Immune Checkpoint Inhibitor Therapies

Inclusion Criteria: * Participant must be ≥18 years of age, at the time of signing the informed consent. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1. * Measurable disease per RECIST version 1.1 (at least one lesion that is measurable by RECIST 1.1. Tumour lesions in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions after radiation) and documented locally advanced or metastatic disease with CT and/or MRI. * All acute, clinically significant (CS) treatment-related AEs from a prior therapy resolved to Grade 1 or lower prior to study entry. Participants with chronic toxicities such as Grade ≤2 neuropathy or alopecia can be included. * Have a life expectancy for disease-related mortality, as evaluated by the investigator. * Male and female participants: Contraceptive use by men or women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. * Adequate haematologic and end organ function * Participant is capable of giving signed informed consent as described in the protocol. Exclusion Criteria: * Have untreated or active primary brain tumour, Central Nervous System (CNS) metastases, leptomeningeal disease, or spinal cord compression. * Experienced severe, life-threatening immune-mediated AEs, or infusion-related reactions such as those that lead to permanent discontinuation while on treatment with prior anticancer therapy such as immune checkpoint inhibitor therapy. * History of known autoimmune disease * History of stroke or significant cerebrovascular disease, encephalitis, meningitis, organic brain disease (e,g., Parkinson's disease) or uncontrolled seizures in the year prior to first dose of study drug. * History of CS cardiac disease within 6 months prior to the initiation of study intervention, including but not limited to unstable angina, acute myocardial infarction, endoscopic or open-heart cardiac surgery, or heart failure classified as New York Heart Association Grade 2 or higher. Additional exclusion criteria include: 1. Left ventricular ejection fraction \<45% 2. QT interval corrected by Fridericia (QTcF) \>470 ms (for women) and \>450 ms (for men) or CS arrhythmias. * History of CS respiratory disease within 6 months prior to the initiation of study intervention, including severe chronic obstructive pulmonary disease or asthma. * Prior organ transplantation. * Chronic or ongoing active infections within 4 weeks prior to Cycle1 Day1 (C1D1). * Presence of hepatitis B surface antigen (HBsAg) \[or hepatitis B core antibody (HBcAb)\] at screening or within 3 months prior to the first dose of study intervention. * Positive hepatitis C antibody test result at screening or within 3 months prior to the first dose of study intervention. * Participants with known history of HIV infection are excluded from the study unless they meet the following criteria: 1. Stable Antiretroviral Therapy: Participants must be on a stable antiretroviral therapy regimen for at least 4 weeks prior to enrolment. 2. CD4+ T cell Count: Participants must have a CD4+ T cell count of at least 200 cells/µL. 3. Viral Load: Participants must have an undetectable viral load (HIV RNA \<50 copies/mL) 4. No Opportunistic Infections: Participants must not have had any opportunistic infections or other human immunodeficiency virus (HIV)-related illness within the past 6 months Note: HIV testing will be performed in any countries where it is mandatory per local requirements. * History of other malignancy within the last years. * Significant concurrent, uncontrolled medical condition that would put participants at unacceptable risk from study participation or preclude them from complying with study procedures per investigator including, but not limited to renal, hepatic, haematologic, gastrointestinal, endocrine, pulmonary, neurological, cerebral, or psychiatric disease. * Treatment with \>10 mg per day of prednisone (or equivalent) or other immune suppressive drugs within 7 days prior to the initiation of study drug. Exceptions may be made for participants who have had allergic reaction to iodinated contrast media. Steroids for topical, ophthalmic, inhaled, or nasal administration are allowed. * Concurrent participation in another therapeutic treatment study. * Participants accommodated in an institution because of regulatory or legal order; prisoners or participants who are legally institutionalised. * For French participants only: participants are under court protection, not affiliated to a social security system or protected adults.