I. INTRODUCTION  
II. BRIEF OVERVIEW OF REINFORCEMENT LEARNING  
A. Reinforcement Learning  
B. Deep Reinforcement Learning  
C. Comparison of RL with other Machine Learning  
D. Why Reinforcement Learning in IoT  
III. THREATS AND RL BASED SOLUTIONS IN IOT SECURITY  
A. Denial of Service Attack  
B. Jamming Attack  
C. Spoofing Attack  
IV. REINFORCEMENT LEARNING IN CYBER PHYSICAL SYSTEMS  
A. Security in Smart Grid  
B. Security in Smart Transportation System  
V. RESEARCH TRENDS AND OPEN RESEARCH CHALLENGES  
B. Learn with partially observable environment  
C. Joint reward from multiple agents  
D. Robustness against Adversarial RL  
VI. CONCLUSION