Metallic-roughness
The PBR workflow that describes a surface with a base color, a metallic channel and a roughness channel instead of a separate specular color.
Three inputs do the job: a base color (albedo), a metallic channel that is effectively zero or one, and a roughness channel running from glossy to matte. If the surface is metal the base color becomes the tint of its reflection and the diffuse term vanishes; if it is a dielectric the reflection takes a fixed pale-grey value. The model grew out of Disney's principled BRDF (Brent Burley, 2012).
It became the default in Unreal Engine 4 (2014) and the canon that glTF 2.0 mandates, and it beat the older specular-glossiness for a plain reason: fewer channels and fewer ways to author a physically impossible surface that reflects more light than it receives.