Offline reinforcement learning is to learn from a fixed dataset without further interactions with the environment. There are many papers focusing on offline RL for a single-agent setting. e.g. https://offline-rl-neurips.github.io/papers.html, However, no literature research on how to learn in multiagent settings. I have tried several state-of-the-art offline reinforcement learning approaches, but it doesn't work well in a multiagent environment. My code can be found here: https://github.com/SHITIANYU-hue/multiagent-offline-RL. The main challenge is how to learn multiagent distribution.