The I See You Tour was in support of an album that was a follow up to what? 
I See You Tour: The I See You Tour was the third concert tour by English indie band The xx, in support of their third studio album "I See You" (2017). I See You (The xx album):  It is the follow-up to "Coexist", and is their first release in more than four years.
"Coexist"