I hear that Deadpool opens with "Mera joota hai Japani" a popular Indian track from some of my friends? Is there any story behind it?


Is it first time that Indian film music has been used in hollywood movie? I don't think so.
What are the other such a cases, I'm just curios to know?

Answer :- 

Yes, it is true. Director of movie, Tim Miller loved this song, that's why he used it.
But Hindi song were used before. Here is the list-
Mundya Tu Bach Ke Rahi (Boom) in The Dictator
Chaiyya Chaiyya (Dil Se) in Inside Man
Mera Man Tera Pyaasa (Guide) in Eternal Sunshine of a Spotless Mind
Chamma Chamma (China Gate) in Moulin Rouge
Chalka Chalka (Saathiya) in Accidental Husband
Bombay theme in Lord Of War
Jaan Pehchaan Ho (Gumnaam) in Ghost World