This is the Retreating Sweater by Samantha Kirby, you can find the pattern on Ravelry.
This sweater went pretty fast, with the exception of the ribbing, now dot get me wrong I like ribbing but this was a lot! The sweater is 100% cotton so by the end of the ribbing it was so heavy. My sister just doesn't like wool. The body knitted up like a breeze though!