Have you heard of Google's Mobile-First Index? It's where Google is going to show different results to people who are using a mobile phone.
Now, some people think that making your website mobile compatible or responsive will solve the problem, but it won't. If you want to do well with Google's Mobile-First Index, follow the link to the brilliant guide from Neil Patel.
What is mobile-first indexing? Generally speaking, when you type a query into Google and your results appear, Google largely determines the results through a desktop-oriented method of ranking. And this used to make sense. But desktop and mobile have different indexing requirements. And since most users conducted their searches on desktops, Google based their method of ranking on desktop indexing requirements. But as you’ve seen, times are changing. Desktop will indeed be around for a long time, but Google has to respond to the reality of increasing mobile traffic.