I don't know why you are being downvoted. Gerrymandering affects congressional districts and has no direct effect on the presidential election.
There are a couple states that assign Presidential electors on a basis of two to the statewide winner plus one to the winner in each Congressional district, rather than winner-take-all, so Congressional districting (including gerrymandering) does have a direct effect on Presidential election s as well as House elections.
Everyone knows that gerrymandering is the only way Republicans ever get any votes — really they should get zero!