Search between a Scarecrow, Pink Hotrod, and a Big Screen is a Challenge in Fortnite Season 4, Week 2. It’s for finding the treasure of the week.
As usual, there’s no need to find the map. You can go straight to the treasure location.
It’s to be found at the named area “Risky Reels” in the north of the map. The screenshots below show the location (blue marker on map, click image to enlarge it):
To ensure correct tracking you should play the match until you get killed. Then you can quit out by holding / . If you leave the match instantly it might not track this correctly. You can double-check this under the Challenges tab in the lobby to see if it counted correctly.