What libraries? If you're writing some pandas code and want to parallelise some part of your data pipeline, as far as I'm aware Pandas doesn't have much support for that, you need to manually use multiprocessing to process different parts of the dataframe on different threads. Yes there are pandas alternatives that claim to be a drop-in replacement with better parallelism support, but the more pandas features you use, the more likely you are to depend on something they don't support, meaning you need to rewrite some code to switch to them.
I am pretty sure you are going to say there is a reason this cannot be done, would just like to know what it is!