The aim of this talk is to present a theoretical and computational approach based on geometric surface partial differential equations (GS-PDEs) to bridge the gap between continuum mechanics and cell biology. Specifically, we employ GS-PDEs to model cell plasma membrane and nuclear envelope mechanics to understand single and collective cell migration in confinement. The cell plasma membrane and the nuclear envelope are modelled as two evolving energetic sharp interface surfaces or manifolds whose evolution is driven by intra- and extra-cellular forces acting at each material point in the normal direction to the surfaces. Cell plasma membrane and nuclear envelope mechanics encode curvature-dependent elasticity, size constrains, cell protrusive forces, as well as forces describing cell-cell interactions and cell interactions with the environment. The theoretical model is solved efficiently by using the evolving surface finite element method with adaptive mesh refinement to allow for large cell deformations. To demonstrate the applicability, generality and novelty of this approach, we replicate several results of biophysical experiments, such as where microfluidic devices are used to impose compressive stresses on cells by driving them through narrow microchannels under controlled pressure gradients as well as how cells overcome basement membrane stiffness to initiate the process of cancer invasion. The modelling approach has made several predictions which are currently being verified in experiments, such as cell behaviour at the exit points of the channels and mechanical measures of cells during cancer invasion. The model reveals that surface tension and confinement geometry emerge as key determinants of cell translocation efficiency. The proposed theoretical and computational framework is sufficiently general to be applied to a broad range of cell mechanics scenarios, providing a robust and flexible tool for investigating the interplay between cell mechanics and confinement. It also offers a solid foundation for future extensions integrating more complex biochemical processes such as active confined migration. Understanding how cells migrate through confined environments is crucial for elucidating fundamental biological processes, including cancer invasion, immune surveillance, and tissue morphogenesis. The nucleus, as the largest and stiffest cellular organelle,