Hi all, I need some guidance on a career situation

I am working in an MNC with about 1 year of total experience. Due to performance issues, I have been put on a Performance Improvement Plan (PIP). I have a few questions:

1. What usually happens if someone fails to meet expectations during a PIP? Will it affect background verification or be mentioned in the relieving letter?

2. Should I start looking for another job during the PIP or wait until it ends? Can I resign in between to avoid a termination record?

3. How badly can a PIP or termination affect future job opportunities with only 1 year of experience?

4. What practical steps can I take to improve my chances of successfully completing the PIP?