The main goal of the Org-BOOST Research Training Group is to advance the understanding of solid tumor biology by employing state-of-the-art 3D organoid models that closely mimic human tumors. Within the frame of three investigational pillars, this initiative seeks to investigate key aspects of tumor development, including onset, cellular plasticity, and interactions with the tumor microenvironment, to identify novel biomarkers and therapeutic vulnerabilities. Special emphasis is placed on integrating human pluripotent stem cell-derived designer organoids, patient-derived tumor organoids enhanced by bioengineering approaches, and computational high-resolution analytics to provide a comprehensive, translational research platform. As a comprehensive research and teaching platform, the Organoid School embedded within Org-BOOSToffers doctoral researchers an interdisciplinary environment combining cutting-edge experimental, computational, and bioengineering methods. It provides structured training through hands-on laboratory skills development, specialized courses in bioinformatics and organoid bioengineering, and emphasizes the development of critical thinking and collaborative abilities. Supported by expert mentorship and access to extensive core facilities, the Organoid School prepares the next generation of scientists to address complex challenges in cancer research with a translational and innovation-driven mindset.