Lots of home treadmills include adjustable slope settings

https://www.hometreadmills.ukbvqh277.greyhavendaily.com/posts/incontestable-evidence-that-you-need-portable-treadmill

Many home treadmills consist of adjustable slope settings, enabling you to mimic outside surface for stronger legs and much better workout variety, whether you're training for hills or burning more calories.