The increasing sophistication of cyberattacks, fueled by generative AI, necessitates a fundamental shift in cybersecurity defense systems, as traditional reactive measures are no longer sufficient against intelligent and evolving threats. Generative AI technologies can detect subtle anomalies, generate defensive strategies, and predict emerging threats before they materialize, allowing organizations to transform their security posture. By leveraging AI-powered anomaly detection, intelligent deception, automated incident response, and predictive risk assessment, cybersecurity defense systems can become more proactive and effective. The successful integration of generative AI into cybersecurity defense requires comprehensive organizational transformation, including the development of strategies that align AI capabilities with existing processes, as well as addressing unique challenges such as model drift, bias, and ethical considerations. Ultimately, the effective use of generative AI in cybersecurity defense can enable organizations to detect advanced threats, prevent malicious behavior, and automate incident response, thereby reducing financial losses and improving overall security.