I want to share my experience with you and talk about viruses created for Mac devices and how to deal with them. You can say that there are no Mac viruses, as Apple does not allow it. However, I can say that there are lots of nasty malware types like adware that open new tabs in your browser, redirect you to irrelevant pages, and display numerous pop-ups.

Yes, these are not real viruses. Adware like Search Marquis cannot clone itself and infect other connected devices. It cannot encrypt your files or cause any other damage. Its activity is only related to online redirects and excessive advertising. At the same time, who knows what junk sites adware may land you on next time. You may end up on a phishing site where cybercriminals hack personal information that leads to identity theft.

FALSE ANTIVIRUSES

I strongly recommend removing all adware that has infiltrated your device. But there is a problem here. If you want to get rid of Mac adware, you can not quickly find a solution. If you go to google and search there how to get rid of Mac malware, you will see that all the best results allow you to buy and install some shady software. In fact, these Mac antiviruses do nothing because we know the Apple ecosystem does not allow apps to access other apps' data. No antivirus can really scan and check your files.

HOW TO REMOVE MAC MALWARE

Solution 1:
If your system is infected with adware and you do not know how to get rid of it, try calling Apple and asking what to do. You can find their phone number here: support.apple.com/en-gb/HT201232#us-ca.

Solution 2:
Another option is to try your luck at the Apple community. Thousands of tech enthusiasts help the use with their problems there. Here is an example of a thread: discussions.apple.com/thread/8226644.

Solution 3:
There are other options as well. Apple operating systems are not very difficult to use, and any person can remove adware manually by going through the step-by-step instructions published on several malware removal sites. Here's a guide from BitAdvisors.com on how to remove Search Marquis malware.

Most creepy software works by exploiting flaws and vulnerabilities in your computer's operating system. And macOS also has its own flaws. To address these vulnerabilities, Apple periodically releases operating system updates. To date, macOS has not proven attractive enough for cybercriminals and malicious developers to flood it with malware.

Tips for protection

To stay away from any surprises, it is recommended to update your operating system as well as any apps that are installed regularly.
You should never install apps from unofficial app stores that are not controlled by Apple.
One of the ways for adware to penetrate your Mac is through the included installations. You download and install a very useful app that is often free, but in reality you get more apps. People never read user agreements written in small letters. There, it may be noted that you agree to install additional tools and grant some rights to them. When installing anything, be careful and read user agreements and do not miss out on extra unnecessary software.
Do not install software without urgent need. Any additional software expands the attack surface.
In order to do bad things, current Mac malware requires users to perform certain actions - assign rights. So be careful about giving any app access to your data, changing settings, etc.
Another wise step is to make backups. iCloud or regular flash drives help you not to lose your data in case of system failure or malware attack.
Final advice - use VPNs. Your connection is being encrypted and attackers cannot find out where you are actually located or what data your traffic is made up of.