Well… the answer is yes, but I can tell you from my experience not many hiring leaders do so. Seems most hiring leaders go straight to the resume.

However, there have been times when a candidate sent me their resume for a job I was working on for my client when the cover letter was more impressive that the resume.

Sometimes the cover letter mentioned some awesome points about their experience, that was not mentioned anywhere in their resume.

There have been times I would have totally passed up on the candidate had I not read their cover letter. In my candidate coaching, the first thing I had that person do was rewrite their resume.

Oddly enough, those that sent me bad resumes with awesome cover letters, I was able to get them an interview and ultimately hired.

In an article written by Fast Company, they do a great job listing what are the components of a great cover letter:
Be interesting
Focus 100% on your value
Think about your Salutation
Keep it short
Show Off (a little)
Proofread
Write Intentionally
Check out the article here to learn more!