The widespread adoption of immune checkpoint inhibitors has significantly improved outcomes across multiple solid tumors but has also increased pressure on hospital-based oncology services, particularly oncology day hospitals. Subcutaneous (SC) formulations of immunotherapy offer a clinically validated alternative to intravenous (IV) administration and may facilitate more efficient, patient-centered models of cancer care delivery. However, the organizational, economic, and governance implications of this transition remain insufficiently explored. We conducted a mixed-methods analysis integrating four components: (1) a structured narrative review of clinical evidence regarding SC immune checkpoint inhibitors, including pharmacokinetics, efficacy, safety, and patient-reported outcomes; (2) an economic evaluation including cost-effectiveness and return-on-investment analyses; (3) benchmarking of national and international decentralized oncology care models; and (4) cross-sectional surveys of healthcare professionals (n = 84) and patients receiving immunotherapy (n = 76). Based on these findings, a hub-and-spoke care delivery framework supported by digital health tools was developed. Across tumor types, SC immunotherapy demonstrated pharmacokinetic bioequivalence to IV formulations, with comparable efficacy and safety profiles. Treatment time was reduced by approximately 85-90%, resulting in improved patient-reported experience and reduced cumulative treatment burden. Adoption of SC immunotherapy was associated with up to 40% reduction in oncology day hospital occupancy and an estimated net annual saving of approximately €1,410 per patient. Both patients and healthcare professionals supported decentralized administration for selected clinically stable patients; however, acceptance was strongly dependent on preservation of oncologist-led care, strict patient selection, digital monitoring, and clearly defined escalation pathways. SC immunotherapy is a clinically effective and safe alternative to IV administration whose principal value lies in enabling selective decentralization of oncology care rather than simple logistical convenience. When implemented within a structured hub-and-spoke model that preserves medical oncology leadership, SC immunotherapy may improve patient experience, optimize healthcare resources, and strengthen long-term health system sustainability without compromising safety or continuity of care.