CSS Grid is a two-dimentional grid-based layout system.
Before Grid existed there were plenty of options for developers to layout web pages, such as these fairly simple options - tables, floats, positioning, inline-block. Flexbox is a better option but it only provides one-directional flow. Each of these elements still have their use cases today and are not irrelavant.
- Grid solves the need for many of the hacks that were needed for the previous elements to work.
- Provides an easy way to structure elements on a page.