Portrait Mode on the new iPhone 11 works with not only human faces, but also objects and pets, according to Apple.
From the iPhone 11 page:
Take portraits to new places. With new kinds of portraits and more lighting controls, the dual cameras in iPhone 11 work together to create stunning images. And Portrait mode now works with everything you love to shoot — that includes your best friends, two‑legged or four.
While this was already possible on the iPhone X, iPhone XS, and iPhone XS Max, Portrait Mode on the iPhone XR was only able to detect human faces in Apple's stock Camera app. (A few third-party apps like Halide did manage to enable Portrait Mode for objects and pets on the iPhone XR.)
There are also six Portrait Lighting effects available on the iPhone 11, including Natural, Studio, Contour, Stage, Stage Mono, and High‑Key Mono. This is up from three on the iPhone XR: Natural, Studio, and Contour.
Portrait Mode automatically creates a depth-of-field effect known as bokeh, allowing iPhone users to shoot a photo that keeps the subject sharp with a blurred background, while Portrait Lighting applies studio-quality lighting effects like black-and-white stage lighting to the Portrait Mode photos.
To use Portrait Mode, open the Camera app and swipe to Portrait mode. Portrait Lighting effects will appear at the bottom of the viewfinder.
iPhone 11 is the direct successor to the iPhone XR, with features including a dual-lens rear camera system with Ultra Wide and Night modes, faster A13 Bionic chip, improved water resistance, six new colors, up to one hour longer battery life, Dolby Atmos sound, 802.11ax Wi‑Fi, Gigabit-class LTE, and more.