A very interesting patent spotted by Patently Apple shows that Apple's considered making phones with both Touch ID and Face ID.
Published in Europe, the patent describes an iPhone with both technologies, with Touch ID standing in as a backup method if Face ID fails.
Apple somewhat zings its own tech while describing why this is needed:
"Techniques for implementing biometric authentication using electronic devices are generally cumbersome. For example, some existing techniques, such as those directed to facial recognition, require a user to almost perfectly align a biometric feature in a same manner during both enrollment and each iteration of authentication.
Deviation from the alignment of the biometric feature often results in a false negative result."
Apple's 3D TrueDepth face scanning is supposed to put an end to that problem, but clearly Apple either thinks it still doesn't work well enough, or is considering having a less sophisticated system on iPhones with a secondary fingerprint option.
Currently, if Face ID decides you are in fact not yourself, you unlock with a PIN code instead. This way, you could use your fingerprint. It's a good idea, because while Face ID is reportedly more secure than the fingerprint method, fingerprints are in turn much more secure than PIN codes.
We've already seen phones with multiple biometric options, like the Huawei Mate 20 RS Porsche, which has 3D face scanning and an in-screen fingerprint sensor. There are also lots of phones with less-sophisticated face unlock features and a fingerprint pad.
While the iPhones pictured in the patent are old-school large-chin designs, that doesn't mean anything because it's a patent about how the tech works, not how it looks. Apple's not going to give away any details about how future phones might look if it doesn't have to.
Of course, the fact that Apple's patented the possibility of Face ID and Touch ID on the same phone doesn't mean it'll actually happen. But people hoping for the return of pressable home buttons can take a little bit of hope from this. [Patently Apple]