The closest thing we'll probably ever get to a Planet Hulk film is Thor: Ragnarok, yet if you want to understand where a lot of the inspiration for the third Thor film came from, then you must read this.
Unlike the aforementioned Thor: Ragnarok, Planet Hulk is strictly a green giant event, the Hulk ending up on Sakaar after Marvel's Illuminati (Iron Man, Doctor Strange, Reed Richards etc.) exile him from Earth. Other familiar faces, like Korg, appear in the story, yet with major differences from their MCU counterparts, with this version of the tale being (like most comics) a lot more serious in tone.
The events of Planet Hulk mainly serve to set up World War Hulk (in which the Hulk returns to Earth). Still, the tale told in this book is one absolutely worth reading in isolation, being one of the best stories to feature Puny Banner's alter-ego in recent years.