The growing demandDemand for cobaltCobalt (Co) and nickelNickel (Ni) in batteriesBattery and electronics necessitates efficient recovery from secondary sourcesSecondary sources like metallurgical wastes and spent lithiumLithium-ion batteriesBattery. Traditional methods, pyrometallurgyPyrometallurgy and hydrometallurgyHydrometallurgy, have drawbacks, including high energy consumption, hazardous emissions, and costly waste management. In contrast, bioleachingBioleaching is an eco-friendly alternative that uses microorganisms to extract metalsMetals through biochemical reactions, reducing energy use and harmful by-products. Certain bacteria, like Acidithiobacillus ferrooxidans, produce acidsAcid that dissolve metalsMetals, while fungi such as Aspergillus enhance recovery via organic acidAcid secretion. Key factors influencing bioleachingBioleaching efficiency include temperature, pH, and retention time. Despite its sustainabilitySustainability advantages, bioleachingBioleaching faces challenges like low recovery rates and inconsistent microbial activity, necessitating research in genetic engineering and process optimizationOptimization. This review examines the microorganisms, methods, and effectiveness of bioleachingBioleaching for Co and Ni recovery, comparing its sustainabilitySustainability with conventional technologiesTechnology and addressing challenges for large-scale applications.