Scientists have been trying to genetically cross breed the American Chestnut with the Chinese Chestnut that has an immunity and to the blight. But it needs to be done in a way to not change the tree too much as the two species are very different. Some do exist in the wild. There's a grove of 600-800 trees in Michigan I believe and there's also a project working on immunity in Eastern PA. More info. https://tacf.org/