When you operate a website, you want to use the right attribute values when you link to other sites. Establishing the right relationship with Google to websites you link to will keep the search engine from penalizing you for unnatural or irrelevant links.
Links are automatically follow if there is no rel attribute value in the a tag. Use rel="nofollow" if you don't want Google to follow the link. Google created the nofollow tag for blog publishers who were overwhelmed by comment spam. Today, many sites besides blogs make user generated content links nofollow by default, including Medium, Wikipedia, YouTube and more.
If you link to a site from your blog because you found the content helpful and relevant, make it a follow link. You're doing the site publisher a favor. Only use the follow attribute when you receive no compensation and you trust the site thoroughly.
Google suggests using the rel="sponsored" attribute for advertising or paid placement links. The new rel="ugc" attribute is for user-generated links, such as blog comment links. According to Google, they now prefer the sponsored and ugc attributes over nofollow in these cases now. You can use both new tags at once if the content is both user-generated and sponsored.
Google says they will use the sponsored and ugo attributes as hints. By gathering information, instead of ignoring the links, Google can still gain important information, including helping them identify link schemes, while understanding that you don't want to endorse the link. These new link attributes should help Google without creating new link spam.
There's no need to go back and change existing nofollow links on your site, per Google. Many SEO experts are also waiting for more information from Google, although they are using the new attributes for new outbound links. For more information click here https://www.reddit.com/r/SEO/comments/hsag3v/tonofollowornotandwhataboutugcand/.