The malware was designed to install a new root certificate, allowing it to intercept communications, even the encrypted ones.
The latest reported Mac threat was the OSX/MaMi. Still, the fact remains that the threat is out there and Mac users are not totally invulnerable to cyber attacks.
Within the last few years, there have been several reports of malware and virus attacks on Macs, albeit not worsening enough to be considered an epidemic. Macs are known for being generally reliable and secure, but just like any other piece of technology, they also have weak points, which may be taken advantage of by unscrupulous perpetrators.