Protoclusters are dense concentrations of galaxies that are forming and evolving in the early universe. They are considered the progenitors of modern galaxy clusters and are believed to play a crucial role in the development of large-scale cosmic structures. Protoclusters are typically identified through their high density of galaxies, as well as their elevated star formation rates and active galactic nuclei activity. Studying protoclusters allows researchers to understand the formation and growth of galaxy clusters, as well as the processes involved in the evolution of galaxies and the intergalactic medium.