Is there a hamburger menu in iOS?
It Clashes with Navigational Buttons on iOS
The hamburger menu placement on the screen is the exact same as the default for the back button: the top left corner.
Why not to use hamburger menu?
One of the biggest downsides of a hamburger menu is that it hides information. Some users don't get the chance to see how much value the app will provide before those 10 to 20 seconds are up. If the hamburger menu icon is difficult to spot, visitors will have a hard time navigating the site. And many will leave.