Graph Neural Networks (GNNs) struggle with out-of-distribution (OOD) recommendation due to unstable correlations.Researchers propose a novel approach, graph representation learning via causal diffusion (CausalDiffRec) for OOD recommendation.CausalDiffRec eliminates environmental confounders and learns invariant graph representations.Experimental results show up to 22.41% improvement in generalization on popular recommendation datasets.