The exploration of Subsurface Access Points (SAPs), such as lava tubes on the Moon and Mars, has gained significant interest due to their potential as stable environments shielded from surface radiation and temperature extremes. These sites are considered high-value targets for detecting water, signs of ancient life, and assessing their suitability as habitats for human missions. However, SAP exploration presents significant challenges, including navigating unknown and hazardous terrains, operating in low-light conditions, and managing limited communication capabilities. Recent advances in high-resolution imaging, Synthetic Aperture Radar (SAR), and other sensing technologies have enabled better identification and characterization of SAPs, providing critical data for potential exploration missions. This review presents a structured critical analysis of the challenges in planetary cave exploration and evaluates the state of the art robotic platforms which offer a cost-effective and safe alternative to human exploration in hazardous environments, in addition to sensor technologies that aid the understanding of SAPs such as seismic studies, geological characterization, and biosignature detection. This article emphasizes the advantages of multi-robot teams in generating comprehensive datasets and improving mission resilience. By combining the unique capabilities of heterogeneous robotic systems, these teams represent a crucial step toward enabling the exploration of SAPs and advancing our understanding of planetary subsurface environments.