Azure Sentinel is a cloud-native security information and event management (SIEM) tool that collects, stores, and analyzes security-related data. It uses machine learning and behavioral analytics to detect threats and automate responses. Azure Sentinel collects log data from various sources through connectors and analyzes the data using built-in queries, notebooks, and workbooks. It leverages the MITRE ATT&CK framework for threat hunting and generates incidents for investigation and remediation of threats.