Before revision: The increasing concerns about data privacy and security drives the emergence of a new field of studying privacy-preserving machine learning from isolated data sources, i.e., federated learning . Vertical federated learning,  where different parties hold different features for common users, has a great potential of driving a more variety of business cooperation among enterprises in different fields.
After revision: The increasing concerns about data privacy and security drives the emergence of a new field of studying privacy-preserving machine learning from isolated data sources, i.e., federated learning federated learning. A class of federated learning, where different parties hold different features for common users, has a great potential of driving a more variety of business cooperation among enterprises in different fields.