In the evolving landscape of digital marketing, "cookieless advertising" emerges as a response to increasing privacy concerns and regulatory constraints surrounding traditional third-party cookies. This shift is driven by significant privacy legislation, like the EU's GDPR and California's CCPA, and actions by major tech companies and browsers, such as Apple's Safari and Google Chrome, to phase out or limit these cookies. As a result, advertisers must innovate with strategies that do not rely on tracking individuals, turning to first-party data collection, data partnerships, contextual and interest-based targeting, and alternative identifiers like unified IDs. Additionally, the industry is exploring AI and machine learning for predictive targeting and data clean rooms for privacy-preserving collaboration. Despite challenges in targeting, personalization, and measurement without cookies, the industry is moving toward more privacy-centric advertising methods, utilizing new technologies and data infrastructures to sustain effective marketing in this new era.