People have been loading Android onto iPhones for years, and now a new hack has been implemented to get Android running on an iPhone 7.
Project Sandcastle is a new effort by a team called Corellium which is actually being sued by Apple right now (via Forbes), with the Cupertino company claiming Corellium broke copyright laws by creating software versions of the iPhone for testing. That hasn't stopped Corellium from figuring out a new way to get Google's mobile OS onto Apple's hardware, though.
You can try a beta version of Project Sandcastle right now. However, there are some restrictions. Project Sandcastle only works on an iPhone 7, iPhone 7 Plus, or iPod touch 7th Gen right now and it relies on the checkra1n jailbreak.
Once you do get Android loaded onto your iPhone, you'll be met with more limitations. Audio isn't supported yet, nor is cellular connectivity, Bluetooth, or the camera. You can't install apps from Google Play, either.
Corellium has taken steps to make running this version of Android on iPhone a bit more interesting to use. That includes preloading the encrypted messaging app Signal.
Because of the limitations, running Android on an iPhone 7 isn't likely something you're going to do for your daily driver smartphone. It's still an interesting hack, though, and it's still in beta so Corellium can continue to work on it and improve it. Plus, it's also just fun to see Android running on iPhone hardware.