Abstract: Copper-indium-gallium-selenide （CIGS） thin-film solar cells have emerged as key candidates in the clean energy sector due to their high photoelectric conversion efficiency, mechanical flexibility, and efficient material utilization. However, the critical dependence on scarce metals such as indium and gallium, coupled with complex extraction processes, has constrained their large-scale deployment. Moreover, retired CIGS modules and manufacturing residues are highly enriched with valuable metals and toxic species, including selenides and cadmium compounds, posing significant environmental and resource risks. Herein, this paper systematically reviews the structural characteristics, service lifespan, resource constraints, and toxicity concerns of CIGS materials, followed by an in-depth analysis of enrichment patterns of high-value components in waste streams. Key recycling strategies namely physical pretreatment, hydrometallurgy, pyrometallurgy, and integrated approaches are critically compared in terms of metal recovery efficiency and mechanistic pathways. Pyrometallurgical roasting, particularly sulfurization and chlorination, effectively disrupts the dense CIGS lattice and enhances solubilization of target metals. Hydrometallurgical methods employing sulfuric, hydrochloric, and nitric acids with oxidants afford ＞90% recovery for Cu, In, Ga, and Se, in some cases exceeding 99%. Solvent extraction using P204 and LIX984 achieves high selectivity and purity in metal separation. Integrated pyro-hydro processes offer a balanced and efficient route for multi-metal recovery. Perspectives on direct reuse of CIGS waste and tailored processes for flexible devices are also discussed. This work provides critical insights and technical guidance for the establishment of a sustainable closed-loop recycling framework for CIGS materials.