I have used rigify to add a rig to my model. However, I can't pose the model in Pose mode. I have checked the model in Weight Paint mode, and everything seems to be painted correctly. I can even manipulate the rig and pose the model in Weight Paint mode. But when I go back to pose mode, only the rig moves and the model does not. I have linked the .blend file.
The issue seems to be the boolean modifier, which cuts your mesh with the nail mesh. when you disable the visibility of that modifier, the armature deforms the mesh as normal. I'm not 100% sure why this happens, if it is an issue due to laggy update because the boolean takes too long, or if the boolean (more likely) messes up your vertex groups, and thus the weights. It's also interesting that weight paint ignores the boolean apparently.