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Go to System Preferences / Settings > Notifications and see if anything associated with either McAfee or "chiosants.com" is shown in the left-hand pane. If so, select it and use the main pane to turn off its notifications.
If it is not there, you may have caught a dose of adware. Those can be manually removed but, by far, the easiest and only safe way to deal with adware is MalwareBytes. It is the product of a trusted contributor here and excels at finding and evicting adware.
Most adware infestations come from visiting unscrupulous download hosting sites that offer "free" what you know would cost money elsewhere. To make their money, they insert a little gift—adware—into the download. Common things that are infected: ringtones; fonts; drivers; screensavers.
To avoid any more adware, get MalwareBytes ONLY from the developer's site: https://www.malwarebytes.com/mac
The free version is run manually. The paid version runs in the background to intercept new incoming "gifts."