Purpose of reviewIn this review, we discuss two case studies in which we summarize the process of expanding patient and public involvement (PPI) representation specific to the head and neck cancer population, highlighting the challenges and successes within each project. The first case study reports on the expansion of HaNC PPI membership, a long-established PPI forum which supports Liverpool Head and Neck Centre research. The second case study describes the establishment of a novel palliative care network in head and neck cancer in the North of England, in which PPI was central to the project's success.Recent findingsWhilst recognizing diversity is important, it is imperative to acknowledge the contribution of existing members. Engagement with clinicians to reduce issues of gatekeeping is essential. A central theme is that the development of sustainable relationships is critical.SummaryThe case studies highlight the challenge of identifying and accessing such a diverse population, particularly in the context of palliative care. Successful PPI is dependent on building and maintaining relationship with PPI members, ensuring flexibility in terms of timing, platforms and venues. Relationships formation should not be restricted to the academic-PPI representative dyad but should consider both clinical-academic and community partnerships to ensure those who are part of under-served communities are afforded the opportunities to become involved in research.