LANDMVRKS and Last Train have put out The Very End Of Every Me, a song with a lyric video that both bands wrote together.
The distinction matters and Metal Underground made it in the first sentence: this is not one band guesting on the other's track. Members of both wrote it collectively. A feature is a favour; this is a different arrangement, and it is rarer because it means neither band owns the song.
The two come from opposite ends of French heavy music. LANDMVRKS formed in Marseille in 2014, under the name Coldsight to begin with, and have four albums on Arising Empire: Hollow, Fantasy, Lost in the Waves and The Darkest Place I've Ever Been. Florent Salfati sings, Nicolas Exposito and Paul Cordebard play guitars, Rudy Purkart plays bass and Kévin D'Agostino has drummed since 2019. Last Train are an alt rock band, not a metal one.