One cannot take Uber from Lima airport (Jorge Chavez International Airport, LIM) to somewhere else, because Uber drivers are banned from the airport. From https://www.peruhop.com/lima-airport-miraflores/ (mirror):
After many reported incidents of inappropriate behavior by drivers, Uber is not a licensed taxi company in Lima. As a result, Uber drivers are banned from Lima Airport by the local authorities. Uber still allows you to order a taxi, but you will find that they then will cancel when they are trying to enter the Airport (as police will be checking permits etc). You may get lucky, and your Uber may get through, but due to safety concerns and legal issues, it is strongly recommended to NOT use Uber at Lima Airport. Official authorities at Lima Airport recommend the official bus service (Airport Express Lima) or one of the official taxi companies inside Lima Airport (Taxi365 or Taxi Directo).
How much does one have to walk at Lima airport (Jorge Chavez International Airport, LIM) to reach an area / street where one can get an Uber cab? I don't know the boundaries of the area where the Uber driver ban applies.