Certificate pinning (or rather, public key pinning) is technically obsolete and browsers themselves removed support for it in 2018. [1] Are there many apps still really using this?
[1]: https://en.m.wikipedia.org/wiki/HTTP_Public_Key_Pinning
The difference between HPKP and certificate pinning is that HPKP can pin certificates on the fly, whereas certificate pinning in apps is done by configuring the HTTPS client in the native application.
Apps like Facebook won't work on TLS MitM setups without using tools like Frida to kill he validation logic.
It's gotten less popular over the years as people keep asking "wait, what are we doing this for again?"; but it's still very popular in certain kinds of apps (anything banking related will almost certainly have it, along with easily broken and bypassed jailbreak detections, etc).
(The end customer isn’t liable for the bank’s inability to properly secure their app from MITM attacks…)