Linux distributions don’t support exFAT natively due to some restrictions by Microsoft (which are patent holders of exFAT). In other words, exFAT is not in the Linux Kernel and needs to be installed by a user who wants to use it. The Debian-based way to to that is:
apt install exfat-fuse exfat-utils
Now you can mount the drive like every other drive.
(source) this page is written in german