The phrase "thing employers" refers to the preferences or qualities that employers look for in potential employees. It encompasses the skills, experience, qualifications, and personal attributes that make a person desirable and suitable for a job.
It's the first thing employers see of you, and hopefully not the last! (inspiringinterns.com)
A summary statement is the first thing employers see when they look at your resume, and it should provide further information about yourself. (resume-now.com)
Everyone knows that one of the first things an employer looks for is previous experience. (internasia.com)