PKP is a certificate verification mechanism to prevent man-in-the-middle attacks and malicious CAs. Google engineers give reasons for low PKP penetration and technical challenges. Google plans to remove support for PKP when it releases Chrome 67 on May 29 next year.
This plan has not yet been determined, the user can still submit objections. According to the survey, in March 2016 all HTTPS sites deployed PKP ratio of 0.09%, to August 2017, the deployment rate increased to only 0.4%.