[1] On 21 May 2017, Muslija made his debut as professional footballer in a 2–1 away defeat against Eintracht Braunschweig after coming on as a substitute in the 70th minute in place of Kai Luibrand.

[6] His debut with Hannover 96 came on 30 September in Matchday 6 of 2018–19 Bundesliga against Eintracht Frankfurt after coming on as a substitute in the 69th minute in place of Julian Korb.

[9] Seven days after debut, Muslija scored his first goals for SC Paderborn in his second appearance for the club in a 3–4 home defeat over Werder Bremen in 2.

[12] On 7 September 2018, he made his debut with Germany U20 in a 2018–19 Under 20 Elite League match against Czech Republic U20 after coming on as a substitute in the 62nd minute in place of Linton Maina.

[15] On 7 September 2019, he made his debut with Kosovo in a UEFA Euro 2020 qualifying match against Czech Republic after coming on as a substitute in the 56th minute in place of Edon Zhegrova.