Blender 4.0 comes with revamped BSDF tool and a wealth of new features | BetaNews
Here's a free Principled BSDF Shader guide to help Blender users, an extract from the free PDF guide and YouTube tutorial below, hope you find it useful :D : r/learnblender
Blender 2.8 How to use PBR textures with principled bsdf Cycles/Eevee - YouTube
How to Use Blender's new ULTIMATE Shader: Principled — Blender Guru
Toon BSDF — Blender Manual
All Blender Principled BSDF Settings Explained - YouTube
114956 - blender 4.0 : Transmission Roughness is missing in Principled BSDF, preventing some textures from being used correctly in previous versions - blender - Blender Projects
How to Use Blender's new ULTIMATE Shader: Principled — Blender Guru