Hybrid, in the ads I've seen tells you the holster materials are a mix of different materials. Some of mine are leather (against your skin on an IWB holster and kydex against the inside of your pants. The leather part is flat and soft while the kydex part is formed to the pistol's contours and locks it into the holster without the need for a thumb strap or lever/locking mechanism.
Some of the hybrid holsters have a type of "breathable" fabric on the inside against your skin to help reduce sweating and moisture soaking of that part of the holster.
I have some holsters that are all kydex except for the plastic or metal clip and screws that attach the belt clip to the belt. I have some holsters that are leather on the inside and kydex on the outside. I have some that kydex on the outside and some type of soft man made material on the inside. All of them work. Some are more comfortable than others.