Personalized AI assistants, a hallmark of the human-like capabilities of Large Language Models (LLMs), are a challenging application that intertwines multiple problems in LLM research.Despite the growing interest in the development of personalized assistants, the lack of an open-source conversational dataset tailored for personalization remains a significant obstacle for researchers in the field.To address this research gap, we introduce HiCU-PID, a new benchmark to probe and unleash the potential of LLMs to deliver personalized responses.