Metamaterials achieve exceptional optical performance via precise manipulation of light's amplitude, phase, and polarization. Recently, high-dimensional design optimization has advanced metamaterial research, enhancing performance and expanding functionalities in imaging, sensing, beam steering, and holography. This focus session explores the latest advancements in high-dimensional metamaterials, focusing on their fabrication, integration, and real-world applications, with the aim of fostering interdisciplinary discussions on breakthroughs, challenges, and future directions.