Unfortunately, it's sort of a trick question. A "return code," in JCL, is a numeric code with a value from 0 to 4095 left by a program when it is called by JCL. Most languages have a mechanism to set this return code. The terms "condition code" and "return code" are often used interchangeably in JCL.
Technically, the only proper use of the term "condition code" is to refer to a two bit value set by most of the machine instructions, but this value is never used by JCL, unless a program explicitly retrieves a "condition code" and returns it as a return code. In Assembler this is moderately difficult, and essentially impossible in any other language. In 40+ years I've never encountered a program that does any such thing.