A Search Engine Results Page (SERP) is the web page that you see after entering a query into your search engine. This page displays links to different websites that contain content relevant to your search.
With 83% of searches being queried through Google (Source: Statista Jan 2022), they maintain the most famous search engine. For better results and great user experience Google has now implemented even more features into their SERP, instead of just organic and paid results, featured snippets, maps, shop, images etc now regularly appear.
These aspects are intended to help users and provide them with the answers to their queries, without them having to further explore. However, for marketers this means that it is much harder for your organic result to be seen, and less likely to be clicked on, even when you have a high ranking.