I have the same use case as wheee09, I tried your trick using the label like this:
_loadingHandle = Addressables.LoadAssetsAsync<T>(new List<object> { _assetAddress, "default" }, null, Addressables.MergeMode.Intersection);
My _assetAddress is a runtimeKey (the hash of the addressable) and I tagged the assets I wanted with the “default” tag (or any other tag I tried for that matter) but no success. All I have is a :
Exception encountered in operation UnityEngine.ResourceManagement.ResourceManager+CompletedOperation`1[System.Collections.Generic.IList`1[UnityEngine.GameObject]], result='', status='Failed': Exception of type 'UnityEngine.AddressableAssets.InvalidKeyException' was thrown., Key=System.Collections.Generic.List`1[System.Object]
UnityEngine.AddressableAssets.Addressables:LoadAssetsAsync(IList`1, Action`1, MergeMode)
But when I use the exact same code without the “default” label:
_loadingHandle = Addressables.LoadAssetsAsync<T>(new List<object> { _assetAddress }, null, Addressables.MergeMode.Intersection);
My assets are properly loaded.
Could you provide us with a little bit more info on how to achieve it @unity_bill ?
See attachment for my addressable setup 
Thank you very much!
EDIT: after testing if I use only the tag like this:
_loadingHandle = Addressables.LoadAssetsAsync<T>(new List<object> { "default" }, null, Addressables.MergeMode.Intersection);
The asset is found. I don’t really understand why the mergedMode intersection with both key doesn’t work.