A Study to Investigate the Pharmacokinetics and Safety of Subcutaneous Rilvegostomig in Adult Participants With Advanced Solid Tumors Previously Treated With Standard of Care Therapy

Inclusion Criteria: * Histologically or cytologically documented advanced (metastatic and/or unresectable) solid tumor. * Participants must have received prior anticancer treatment for the disease under study. * IO monotherapy deemed appropriate by the investigator. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at enrollment with no deterioration. * Minimum life expectancy of ≥ 12 weeks at enrollment. * Adequate organ and marrow function. * Body weight ≥ 30 kg. Exclusion Criteria: * Any severe or uncontrolled systemic diseases, which makes it undesirable for the participant to participate in the study or that would jeopardize compliance with the protocol. * History of organ transplant. * History of another primary malignancy that was active within past 2 years. * Persistent toxicities caused by previous anticancer treatment(s) excluding alopecia, not yet improved to Grade ≤ 1 or baseline. * Unstable, symptomatic brain metastasis or spinal cord compression. * History of leptomeningeal carcinomatosis. * Active primary immunodeficiency/active infectious disease including tuberculosis (TB), human immunodeficiency virus (HIV) infection or hepatitis A, B or C infection. * History of clinically significant arrhythmia, cardiomyopathy of any etiology; symptomatic congestive heart failure, history of myocardial infarction within the past 6 months. * Uncontrolled intercurrent illness including but not limited to ongoing or active known infection; interstitial lung disease (ILD), serious chronic gastrointestinal conditions associated with diarrhea; active non-infectious skin disease requiring systemic treatment. * Active or prior documented autoimmune or inflammatory disorders requiring chronic treatment with steroids or other immunosuppressive treatment. * Known allergy or hypersensitivity to rilvegostomig, hyaluronidase, or any excipients of the investigational products. * Participants experienced a toxicity to prior immunotherapy that led to permanent discontinuation of prior immunotherapy. * Prior anticancer treatment, including immunotherapy, up to 28 days prior to the first dose of study treatment.