The Solid Earth structure beneath Greenland and Antarctica is gaining an increased interest in recent years as it provides a critical boundary condition for the dynamic evolution of the overlying ice sheet. So far no consensus on some of the key structures and parameters is reached and some studies suggest to ignore or use of an ensemble of Solid Earth models as their uncertainties might otherwise lead to unrealistic predictions. We invite contributions working on sub-glacial geology and tectonics to studies addressing the overall lithospheric structure from. Hereby, novel approaches to describe the sub-ice setting (based on machine learning) and integrated joint inversion methods are invited that bridge data to models to describe key parameters for an improved understanding of Ice-Solid Earth interaction.