>>326620021
You have to use a shader that supports alpha cutouts if you've got a texture with an alpha channel.
I would recommend importing Arktoon for your first try because of it's ease of use.
https://github.com/synqark/Arktoon-Shaders/releases/download/1.0.2.6/arktoon-shaders-1.0.2.6.unitypackage