I think,here are the list of three biggest changes
you’ve seen in SEO within the last year or two:

1. Topic-based content clustering

In the past, content for SEO is simply using the target keyword(s) naturally within the content with a certain density. The same idea still applies today, but Google (and other search engines) are now smarter in determining whether a site is indeed relevant for a certain keyword and for the topic/niche that includes the keyword. So, today we will need a more holistic approach with our content, and we should develop more than one content pieces to cover a topic, establishing relevance.

2. Voice search

More and more people are using voice-based search queries either on their mobile devices or Amazon Alexa (and similar home assistant devices). Meaning, we should optimize for these “voice keywords” and since a huge majority of this voice search are with local intent (“near me” queries), local SEO for Google Maps ranking is now also a must, especially for local brick-and-mortar businesses.

3. Amazon Search

This is especially prevalent for e-commerce businesses. More and more people nowadays directly search on Amazon when looking for products, and so we can almost say that Amazon is the Google of e-commerce. SEO in Amazon require a relatively different approach, and will affect our overall strategy.