Progenitor stars are the massive stars that undergo a supernova explosion at the end of their lifecycle. They are responsible for seeding the interstellar medium with heavy elements and shaping the evolution of galaxies. Studying progenitor stars can provide insights into the processes of stellar evolution, supernova explosions, and the production of elements essential for life. Researchers use observational data, theoretical models, and simulations to study progenitor stars and better understand the lifecycle of massive stars.