Google seems to be testing a new UI for some SERP features like Related Search, People Also Search, etc where they show each entry with a + in front of it and on clicking it the page loaded a new search with the selected term.
Read More: is-testing-a-new-ui-for-related-search-people-also-search-where-they-refine-the-serps-on-clicking-them/">Google is Testing a New UI for Related Search, People Also Search Where They Refine The SERPs on Clicking Them