Influencer marketing focuses on delivering your brand message to a targeted set of industry influencers rather than to the market at large, relying on those influencers to amplify your voice to a relevant and pre-qualified audience.
Influencers have earned the trust and loyalty of a very large and relevant audience, they tend to have more sway. Their following is likely larger and more diverse than the audience whom your marketing efforts are currently reaching, and is often comprised of people that are deeply invested in your target niche. When influencers amplify your voice (via guest posting on their site, mentioning you on social media, or otherwise engaging with you), your message reaches a larger audience that's naturally more receptive to sharing and linking because they trust the influencer.