Well if I understand correctly, you want the HDRI to have clouds animation? If that’s the case you really can’t, unless you make a VFX shot with alpha and lay over the cloud animation and then use the animation in the world texture, but that’s crazy. It’s more of a VFX shot more than anything, something you do in post-production, but that’s a whole different game. You can though have the clouds in your scene and leave the HDRI as a background. Hope that helps.