As in it doesn't really matter, its not a big issue/problem or that something is not impressive or news worthy

a big deal = a big problem or a major event We use it very often in a negatively phrased way, i.e., "It's not a big deal." Examples: "I'm sorry, Mom. I spilled wine on your sweater." "Don't worry. It's not a big deal. Your Aunt Trudy gave me that sweater for my birthday, and I've never liked it." "I'm so nervous. I have to go to the hospital tomorrow to have my tonsils removed." "Tonsils? Don't worry. Having your tonsils taken out is not a big deal. It's a very common procedure."

not a problem, nothing to worry Hope this helps :)