To meet the requirements of ubiquitous connectivity, the sixth-generation (6G) is expected to support higher frequencies such as millimeter waves and terahertz, as well as high-mobility scenarios like unmanned aerial vehicles and vehicular networks. However, communication scenarios under these conditions may suffer from beam misalignment due to high mobility, especially in high-frequency channels with narrow beam characteristics. Integrated sensing and communications (ISAC) enable hardware and spectrum resource sharing between radar sensing and wireless communication, and exhibit great potential in sensing-assisted communication. One pressing problem is that performance metrics for sensing and communication are often contradictory when they share the same hardware or wireless resources. Therefore, how to optimize the performance metrics between both is the key to fulfilling specific requirements. This article focuses on ISAC enabled predictive beamforming for 6G high-mobility scenarios, and investigates the technical characteristics, system architecture, and optimization schemes involved in the performance trade-offs. We first provide an overview of the unique characteristics of ISAC and predictive beamforming and highlight the benefits of combining them. We then investigate the design architectures and propose an optimization scheme that can achieve a performance trade-off between sensing and communication to maximize throughput. Finally, we highlight some challenging issues that need to be addressed in practical implementations.