Fungi have evolved many symbioses including different eukaryotes and prokaryotes. Mutualism is one of the symbioses and here both symbionts benefit from the interaction. The most common mutualistic relationships involving fungi are mycorrhiza and lichens. A mycorrhiza is a symbiotic relationship between a roots of a plant and a fungus while lichen associates between a fungus and an algae. Many studies have performed to investigate these symbiotic relationships in depth, however, still have some debates on them, though many taxonomists rely on genetic analyses besides with traditional morphological data. In our study, it highlights the nature, importance, nutritional and pharmaceutical uses, and applications of these mysterious dual between fungi and plant and/or algae.