A much discussed question in the glossopoetic community!
My take on this is that while some lexicon seems to overlap between natural & invented languages on the one hand and machine programming languages on the other hand, really, the latter are not all that close to the former in either form or function.
Constructed Languages are those life-imitating objects d'art that are or could be intended for communications between living, thinking, self-aware beings. They range from the purely aesthetic & artistic to the engineered to the auxiliary mode of communication. But they all share a fundamental basis in the language using capacity of the sophont mind. We use language. We assume that the peoples in our fictional worlds use language. Invented languages are the token representations of the actual languages of those other people.
Programming Languages are (sub)sets of code used to instruct a machine to do something, to produce an output. As such, this Stack really isn't the place for programming language questions. Now, that said, some folks in the past have tried working on e.g. human-machine constructed interlanguages. Questions about these kinds of works I think ought to allowable.