If the site is using Cloudflare (free), AWS CloudFront (cheap), or another CDN, it won't have a unique IP address. For now, the domain name will still leak in plaintext through DNS and over the TLS connection in the SNI field, but browsers are planning to implement DNS over HTTPS [1], and encrypted SNI is on the way [2].

[1] https://blog.nightly.mozilla.org/2018/06/01/improving-dns-pr...

[2] https://news.ycombinator.com/item?id=17401509