Understanding the reservoirs and cycling of volatiles deep within planetary interiors is crucial for unraveling the physicochemical processes that drive planetary evolution. Volatile elements such as carbon, hydrogen, and nitrogen can readily interact with mantle and core materials under extreme conditions, profoundly affecting their properties. This talk will delve into the cycling of volatiles through planetary interiors and their interactions with mantle and core materials, emphasizing the importance of advancing technical capabilities to simulate extreme conditions. By tracing volatiles from the crust to the core, we can gain insights into core chemistry, the pathways of volatiles from planet formation to the present, and the broader thermochemical evolution of planetary systems.