Regarding the Wisconsin Senate race, Republicans normally clean up in the Milwaukee suburbs and Johnson was no exception. Trump still won those suburbs, but underperformed relative to Johnson. Johnson won the "WOW" (Waukesha, Ozaukee, Washington) counties north and west of Milwaukee by almost 143K votes, Trump won them by less than 108K.
Trump also generally underperformed Johnson in the cities. Milwaukee County and Dane County (Madison) make up the Democratic power base in Wisconsin, so it's not surprising both Johnson and Trump lost those counties by wide margins. But while Johnson lost them by a collective margin of over 268K votes, Trump did even worse, losing by just over 309K. Trump similarly underperformed Johnson in most counties that were home to smaller cities like Green Bay, Appleton, La Cross, or Eau Claire.
Where Trump did better than Johnson is in rural parts of Western Wisconsin where Democrats have traditionally won. Lafayette, Crawford, Vernon, Richland, and Columbia Counties all went Feingold/Trump, while no counties went Johnson/Clinton. Trump also outperformed Johnson in most Feingold/Clinton and Johnson/Trump counties in Western Wisconsin. It wasn't enough to make up Johnson's "advantage" in urban and suburban counties, it was enough to win the state.
Long story short, the story painted by the Johnson/Trump comparison is a pretty familiar one for the election. Trump cleaning up in rural areas (even by Republican standards) while losing ground in the suburbs.