  The 3rd Generation Partnership Project started the study of Release 18 in
2021. Artificial intelligence (AI)-native air interface is one of the key
features of Release 18, where AI for channel state information (CSI) feedback
enhancement is selected as the representative use case. This article provides
an overview of AI for CSI feedback enhancement in 5G-Advanced. Several
representative non-AI and AI-enabled CSI feedback frameworks are first
introduced and compared. Then, the standardization of AI for CSI feedback
enhancement in 5G-advanced is presented in detail. First, the scope of the AI
for CSI feedback enhancement in 5G-Advanced is presented and discussed. Then,
the main challenges and open problems in the standardization of AI for CSI
feedback enhancement, especially focusing on performance evaluation and the
design of new protocols for AI-enabled CSI feedback, are identified and
discussed. This article provides a guideline for the standardization study of
AI-based CSI feedback enhancement.
