I. Introduction

II. Background  
A. Metaverse and XR: An Introduction  
B. Architecture of Metaverse  
C. Interoperability of Metaverse  
D. AI for Metaverse  
E. ML Security Issues  
F. Secure Data Sharing

III. Challenges in Metaverse  
A. Metaverse Related Security and Safety Issues  
B. Metaverse Related Privacy Issues  
C. Trustworthy AI and AI-Related Privacy Issues  
D. General Challenges

IV. Solutions for Assuring Privacy in AI-XR Metaverse  
A. AI-XR Metaverse Privacy-Enhancing Technologies  
B. Homomorphic Encryption (HE)  
C. Differential Privacy (DP)  
D. Privacy Preservation for AI-XR-Enabled Metaverses  
E. Solutions for AI Associated Privacy Issues

V. Insights and Pitfalls  
A. Distinctive Privacy Challenges in the Metaverse  
B. Copyright Protection and Personal Data Management  
C. Blockchain and Smart Contracts for Data Management  
D. Regulatory Challenges and Policy Considerations  
E. Empowering Users and Ensuring Transparency

VI. Open Research Issues  
A. Human Computer Interaction Issues  
C. Embedded/Edge ML for Enhanced Data Privacy  
D. Taking a Human-Centric AI Approach  
E. Blackbox Nature of DL-Based AI Models

VII. Conclusions