Despite looking online for answers to this problem, I have come up still empty handed. My humanoid model will not move with his bones in pose mode. The mesh is parented to the armature, the vertex groups and bones are named the same to their respective parts, the armature modifier is active on the mesh, the bones are set to deform, the whole mesh has a weight of 0, etc. I am using empty groups, and have assigned each vertex group to the areas I want them to move. I tried using automatic weights, which worked for some reason, but the vertex groups were a mess, and so I redid the vertex groups and it did not work. I tried re-parenting the mesh to be with empty groups after trying that, and it still does not work.
If weights are 0 (if vertex groups are empty) the mesh will not move.
In edit mode select all vertices of a section of your mesh (i.e. left hand), select the relevant vertex group (maybe hand.l) and assign a weight of 1.0. Do the same with the rest of the body. Then use smooth brush in weight paint mode to soften the transitions.