The recent advancements in privacy-preserving technologies have significantly influenced various fields, particularly in healthcare and human-robot interaction. Federated learning (FL) has emerged as a cornerstone, enabling collaborative model training across decentralized data sources while maintaining strict privacy. This approach has been particularly impactful in medical imaging and brain-computer interfaces, where the need for large datasets and stringent privacy requirements are paramount. Innovations in FL, such as the integration of differential privacy and secure aggregation, have demonstrated near-equivalent performance to non-private models, addressing critical privacy concerns in healthcare data management. Additionally, advancements in homomorphic encryption and synthetic data generation have further fortified privacy-preserving practices, offering new avenues for secure data sharing and analysis. Notably, the application of FL in human-robot interaction has shown promising results in complex command classification and occlusion prevention, enhancing the practicality of multi-robot systems. These developments collectively underscore a shift towards more secure, efficient, and collaborative data-driven solutions across diverse domains.