The flow instabilities in subsurface porous media are widely encountered in the environment-energy nexus such as soil and water contamination, CO₂ sequestration, enhanced oil recovery, geothermal recovery, underground hydrogen storage, methane-gas migration in ocean sediments, and iron-rich layer and salt evolution. Two major types of fingering instabilities are commonly observed: capillary fingering and viscous fingering, with multi-physics involved such as interfacial tension, diffusion, dispersion, dissolution, heat transfer, reaction, inertia, gravity, and solid deposition. Understanding the origin and mechanisms of fingering instabilities is important for the design and control of processes related to subsurface flow settings as encountered in environmental and energy systems. In this session, we invite researchers to present their recent advances on (1) novel experimental studies and findings on the new physics and mechanisms for fingering instabilities; (2) advanced theoretical and numerical modeling of fingering instabilities at different scales; and (3) implications of fingering instabilities for various applications.