Review on 🔌 Fotag OBD2 16 Pin to DB9 RS232 Serial Port Adapter Cable with Power Switch - 1.5M 5ft by Travis Oetting

From the description it says it converts ODB2 signals to an RS232 signal, presumably for connection to a computer that has the appropriate decoding software installed. In fact, it just takes a subset of the ODB2 signals and routes them to pins on the DE9 connector, which is commonly used for RS232 connections to a PC. There is an industrial CAN connection scheme which is a DE9 connector so I am assuming this cable is to allow the automotive ODBII to interoperate with the industrial network.