A landrace strain may be either depending on where it is from.
Landrace strains adapted to warm or tropical environments (Thai, Durban) tend to be sativas, with long, leggy stalks and thin leaves, whereas landrace strains in colder climates (Hindu Kush) developed shorter, bushier plants with reduced flowering times.
When these landrace strains are crossbred into new combinations, and genetics are mixed, the indica and sativa labels become largely irrelevant.