How to prevent someone clone PIC
There isn't a way to do this with a PIC, from what I've read there are also labs in china that can defeat code protections on a PIC. Even microchip admits this:


  Very often the intellectual property (IP) of an embedded product lives
  within the code of the microcontroller. In today's market place, it
  only takes a few weeks to extract that code despite the usage of
  traditional "code protect" features. At a moderate expense, many third
  party options are widely available on the internet who are capable to
  obtain HEX files from the microcontroller. This type of conterfeit
  puts in danger companies IP and could consequently lead to significant
  revenue loss or open various backdoors to malicious firmware.


Source: https://www.microchip.com/design-centers/security-ics/cryptoauthentication/counterfeit-protection/secure-boot

But they do have the ATECC608A to secure boot a PIC and even obfuscate I2C communications to prevent copying.