Google Chrome will warn users when submitting insecure forms that deliver information via HTTP connections on HTTPS websites starting with version 86. These forms (also known as mixed forms) are both privacy and security risks for users since they can allow attackers to read or modify the submitted data. Chrome is also planning to fully block mixed content downloads from sites to protect Chrome 86 users from man-in-the-middle (MiTM) attacks. Google has also announced in October 2019 that Chrome will gradually also start blocking HTTPS pages from loading insecure resources.
Source: https://www.bleepingcomputer.com/news/security/google-chrome-will-warn-users-when-submitting-insecure-forms/