Marketing Module vs. Microsoft Dynamics Marketing vs. Microsoft Dynamics 365 for Marketing

Hi there,

I am new to MS Dynamics CRM. Currently, our marketing team isn't using any marketing automation or software. When talking to our IT manager, he mentions about opening up MS Dynamics marketing module for our needs.

I want to understand are there 3 different things and which one is sunsetting? 

1. Marketing Module

2. Microsoft Dynamics Marketing

3. Microsoft Dynamics 365 for Marketing 

Thank you!