Are two quite different lines.
Debian dates back to the 1990s as one of the original distributions.Debian is still a community drive distribution.
Debian is known for being very stable, but lagging behind with development and hardware support.
Debian uses the APT rail with .deb as the package format for package management.Debian is mainly used in server and home users.
Fedora only emerged as an offshoot of Red Hat Enterprise Linux in 2003 and has become an upstream variant.
Red Hat is primarily used in the server sector and, unlike CentOS, for support needs.
Red Hat is primarily a paid version and Debian is a free distribution.Fedora is also free.
Red Hat is developed by an amerkan software company.Fedora is a distribution with Red Hat-supported Community Drive.
Red Hat and offshoots use Red Hat Package Management for package management with .rpm package format.
Fedora is known for implementing new technology very early on.For example, it was one of the first, if not the first, distribution that Wayland introduced as the default and replacement for the X server. Which, in my personal opinion, still does not find a mainstream appeal and is still under-supported. Fedora goes to version 30 in April and has already used Wayland for the first time with version 25 in 2016. For example, Ubuntu only tried this in version 18.10 (October 2018) and still uses the X-Server for the currently long-term support variant 18.04. The next long-term support version will not be released until April 2020!
Fedora is often used ill-considered as a desktop distribution.However, as an upstream of Red Hat Enterprise Linux, it is actually to be seen as a live development environment. In this respect, Fedora should primarily be used by developers who are primarily interested in the Red Hat rail.
The Red Hat rail is more likely to be seen as a small special area rail.The Debian rail is again seen in broad dispersion and as mainstream.
Debian has produced Ubuntu as an offshoot.And that’s where Mint comes from. Among numerous other distributions.
The Debian rail with APT Package Management is to be seen as a great mainstream rail.
The rail is very well known and various options are often used in the desktop area.The most important ones can also be found in various lists for desktop distributions and are regularly ranked high.
Google, for example, has used a slightly modified version of Ubuntu as the standard operating system for employees for years.In return, there were contributions to development. In the meantime, Google has switched to a Debian base.
Debian itself, e.g. in the area of desktop and servers.Mint rather in the desktop area. Ubuntu in the desktop and server area. Ubuntu has also tried its hand at the mobile sector. For example, with Ubuntu Touch for smartphones. In addition, this rail supports various architectures. For example, the default operating system for development boards such as Raspberries (Raspbian) is based on Debian. On the side of Ubuntu there are also images for ARM and Apple Mac.