The search for this specific title primarily yields fan-made . It is likely you are looking for one of the following:
Another iconic Gürses track often used in rap remixes and featured in modern media (like the Çukur series, where Gazapizm also had music). Muslum Gurses Feat Gazapizm Bir Gun
There is no official collaboration titled "Bir Gün" by featuring Gazapizm . The search for this specific title primarily yields fan-made
Müslüm Gürses passed away in 2013, so any "new" releases featuring contemporary rappers like Gazapizm are typically posthumous mixes created by DJs or producers. Bir Gün Yalnız Kalırsan Muslum Gurses Feat Gazapizm Bir Gun