Explore the intricacies of parton distribution functions in this 20-minute conference talk by Huey-Wen Lin from Michigan State University, presented at the 2022 Snowmass Theory Frontier Conference. Delve into traditional methods, the concept of the "holy grail" in this field, and the latest calculations and publications. Examine short distance physics versus lattice calculations, current status of research, physical parameters, and other related studies. Gain insights into the challenges faced in this area of particle physics and engage in a discussion on polarized PDF. This talk, part of the Particle Physics Community Planning Exercise, offers a comprehensive overview of recent advances and future opportunities in high-energy physics theory.