They're working on something called "Project Periwinkle" that is intended to remove all Heroku branding and make everything Salesforce branded. Periwinkle being a colour between blue (salesforce) and purple (heroku). No more Heroku signups, you'll need a Salesforce account to use it. No more free tier either.
Heroku has been in the process of being sunset for years now. New features have been banned for years. Only "keep the lights on" projects are allowed. Not that they could do anything with the skeleton crew they have running the platform.
Bob Wise's LinkedIn doesn't even mention Heroku, only Salesforce. Lenora mentions the project here: https://www.lenoraporter.com/portfolio/salesforce
Source: I'm a former employee that left in protest because of this project.