My apologies in advance for what is likely a rather ignorant question, but I could not find any answers online to my issue. I'm entirely self-taught with ArcGIS Pro 2.3 and have been using it to create some least-cost paths for my dissertation in history. I've been using a DEM up until now for my paths, there being a lack of satellite surface data for seventh-century Italy. I want to add in some Roman roads to see how this would affect the paths. So I made the road in my study area in a polyline, which I then converted to a raster. I then took my DEM and calculated the slope, like I always would when doing a least-cost path, and then I reclassified the slope, with the lowest values having the least slope. Next, I reclassified the road polyline, giving the whole thing a value of 1. Then I ran the combine tool, and what I got is the line in the image. It combined them just fine, but somewhere along the way it removed the rest of the slope raster! I tried weighted overlay, but that did not change anything. What did I do wrong?