If you are getting notifications from LeadingSystem, then your Mac is infected with adware. LeadingSystem is adware for Mac.
LeadingSystem changes setting in your Mac. First, LeadingSystem installs a browser extension in your browser. Then, after LeadingSystem hijacks your browser, it modifies settings in the browser. For example, it changes the default home page, modifies search results, and displays unwanted pop-ups in your browser.