There are a lot of good ideas on how the gameplay can be changed in such a way that it will lessen the advantage a cheater has, but at the end of the day it's more or less impossible to prevent cheating completely, so the question becomes how to handle that given the wish for a global leaderboard.
Personal leaderboard or a leaderboard for friends only
First of all I just have to mention that maybe the best idea is to ditch the idea of a global leaderboard. As much fun as those can be with a healthy community, they end up with a lot of issue. Even in something as innocent as a bridge building game you end up with people using bugs in the physics engine to take the top spots thus ruining the fun for normal players.
An easy way to 'fix' this is to only put friends on the leaderboard, because that way at least the large large majority of players won't encounter cheaters and the leaderboard will still be a meaningful goal.
Normal and tool assisted leaderboard
Only applies if cheating is fun
Players are surprisingly honest typically. I have once seen a game which literally asked 'Did you cheat? Just be honest, we wont punish you.' at the end and if you said 'Yes' it put you on a different leaderboard. In that case the 'cheating' was playing with two players which the rules prohibited explicitly, but I could totally see a situation where people who 'cheat' will be competing on a tool assisted leaderboard and people who don't cheat will compete on the normal leaderboard.
Time constrained leaderboard
Only applies if cheating is not fun
Lastly it's useful to note that typically repeated cheating is not fun, as it often makes it trivial to win. This thus means that repeatedly wiping the the leaderboard (e.g. by having a daily leaderboard only) makes both the reward for and damage from cheating minimal.