Have you ever received a similar email?

I’m with XXXXX — we have a domain rating (DR) of 50. I checked and yours is 40. I’m suggesting a swap that benefits you. I’ve got our SEO team ready to insert your link, which your positive reply would set in motion. Are you game? 

I am sure there is something I don’t get here.

Why would they text me to ask permission to add a link to my domain?

What’s their next step? Asking a fee to do that?