Does iPhone Xs Max have a SIM card slot?
Yes. Dual SIM iPhone Xs Max does have a regular nano SIM card slot and additionally an eSIM.

There's no such thing as an eSIM only iPhone.

From the iPhone Xs Max Tech Specs web-page:



Quoting the footnotes from the Tech Specs page:


  eSIM will be available later this year through a software update. Use of eSIM requires a wireless service plan (which may include restrictions on switching service providers and roaming, even after contract expiration). Not all carriers support eSIM. Use of eSIM in iPhone may be disabled when purchased from some carriers. See your carrier for details. To learn more, visit https://support.apple.com/kb/HT209044.


From the linked support article, Learn about Dual SIM with your iPhone Xs or iPhone Xs Max:


  You can use two cellular plans with your iPhone Xs or iPhone Xs Max, a nano-SIM, and an eSIM. An eSIM is a digital SIM that allows you to activate a cellular plan from your carrier without having to use a physical nano-SIM. Here's how to set up and use a cellular plan using an eSIM


Additionally, exclusively for Chinese Market, Apple has introduced a dual SIM iPhone with support for two nano SIM cards without an eSIM.

Quoting from the support article, Learn about Dual SIM with iPhone Xs Max in China, Hong Kong, and Macau


  In China, Hong Kong, and Macau, you can use Dual SIM with your iPhone Xs Max and two nano-SIM cards. This gives you two phone numbers to make and receive calls and text messages.