The landscape of cyber threats is constantly changing, with spear phishing representing a particularly stealthy and prevalent risk. This review paper examines the integration of Artificial Intelligence (AI) in combating spear phishing, through an in-depth analysis of 23 pivotal studies. It highlights the progression of AI-enabled detection technologies that employ advanced algorithms to identify and mitigate sophisticated email threats. The coverage extends across a variety of AI methodologies, such as machine learning, natural language processing, and behavioral analytics, demonstrating their effectiveness in detecting malicious email activities that conventional security protocols often overlook. Our review identifies significant strides in utilizing AI to combat the subtle and evolving nature of spear phishing attacks but also acknowledges the emergence of new challenges, including adaptability issues, increased false positives, and the necessity for ongoing adaptation to address emerging threats. This paper elucidates the ongoing battle between spear phishing strategies and AI-based defenses, providing insights into future directions for research and innovation in the vital area of cybersecurity.