IL-2 PET Imaging in Advanced Solid Tumours

Inclusion Criteria: 1. Age ≥ 18 years at the time of signing informed consent. 2. Patients with histologically confirmed diagnosis of locally advanced or metastatic solid cancer, eligible for ICI therapy as part of routine care. 3. At least 1 lesion that is accessible per investigator's assessment and eligible for biopsy according to standard clinical care procedures. 4. Measurable disease, as defined by standard RECIST v1.1. Previously irradiated lesions should not be counted as target lesions except for lesions that have progressed after radiotherapy. 5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 6. Life expectancy ≥ 12 weeks. 7. Signed informed consent. 8. Willingness and ability to comply with all protocol required procedures. 9. For female patients of childbearing potential and male patients with partners of childbearing potential, agreement (by patient and/or partner) to use a highly effective form(s) of contraception (i.e., one that results in a low failure rate (\< 1% per year) when used consistently and correctly)). Exclusion Criteria: 1. Treatment with any other investigational agent or participation in another clinical trial with therapeutic intent within 28 days prior to \[18F\]AlF-RESCA-IL2 injection. 2. Evidence of an active infection that requires systemic antibiotics within 2 weeks prior to \[18F\]AlF-RESCA-IL2 injection. 3. Any other diseases, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of \[18F\]AlF-RESCA-IL2, or that may affect the interpretation of the results or render the patient at high risk from complications. 4. Altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent. 5. Sponsor employee/member of the clinical site study team and/or his or her immediate family 6. Pregnant or lactating females. 7. Concurrent use of systemic corticosteroids \> 10 mg daily prednisone equivalent.