If the PIP is merely a form of being soft-fired, then give it a token effort and seriously look for a new job.
If there really is room for improvement on your part in some specific area, then why not work to the program and see if you can make an improvement? I would still start looking for new work as a plan B.
I had a client who was put on a plan and they hoped he would quit. He was irked but he stayed. The manager eventually quit.