Since their discovery in the early 2010s, innate lymphoid cells (ILC) have been increasingly recognized for their roles in cancer pathogenesis, exhibiting both pro- and anti-cancer activities. However, the inconsistent use of phenotypic markers for their identification has hindered progress in utilizing ILC for cancer prognosis and therapy. ILCquest aims to overcome this obstacle by standardizing methodologies for the identification, isolation, and cultivation of ILC, thus enabling accurate and reproducible quantitative and qualitative assessment of ILC during cancer pathogenesis, and design of novel ILC-targeting drugs. Leveraging a comprehensive pan-European network of experts in basic and clinical immunology, systems biology, synthetic chemistry, biochemistry, computational modelling, medical biotechnology and clinical oncology, this initiative will create a unique collaborative platform – the European ILC Network. This network will facilitate consortia creation for joint research proposal applications and serve as a hub for training and capacity-building, promoting best practice, and elevating ILC research quality and reproducibility, that way ensuring sustained impact beyond the project’s lifespan. Through close communication and dissemination of ILCquest results to policymakers, R&D professionals, and biotechnology and pharmaceutical companies, the use of ILC in cancer prognosis and therapy will be significantly advanced. By integrating diverse expertise and embracing the fresh perspectives of early-career investigators and innovators, ILCquest aims to deepen our understanding of ILC in cancer. This systemic approach will pave the way for future clinical trials and support the development for novel cancer diagnostic tools and immunotherapies, addressing a critical and growing global health challenge.