Led by Yongquan Qu, this study presents PnP-DA (Plug-and-Play Data Assimilation), a new method to improve forecasts in Earth system models. As part of the LEAP project, the team combines lightweight analysis updates with a pretrained generative prior to overcome the limitations of traditional approaches that assume overly simple error statistics. Tests on chaotic systems show that it consistently reduces forecast errors across a range of conditions, outperforming classical data assimilation methods. This approach points toward more reliable and efficient forecasting tools for complex Earth system dynamics.