An upcoming update to iOS 12 is expected to add support for depth of field (DoF) control to the iPhone XS range's camera. With this feature, you'll be able to adjust the DoF while taking a photo.
Depth of field RSS
Instagram is rolling out a feature on its iOS and Android apps that it calls 'Focus', which serves to blur out backgrounds once it detects a face in the shot, to produce a fake depth-of-field.