Threat Hunting is a proactive method. It's a way of looking for adversaries actively, identifying known malware, performing anomaly detections, and utilizing the threat intelligence information.
Incident Response is reactive, and the process starts after the team received an alert or notification. Majority of the organization starts from reactive (IR) and slowly moves to the Threat Hunting as they mature. Threat Intelligence plays a crucial role in the success of the IR and TH Programs in any organization.