The frequency of the sickle cell allele in areas where malaria is introduced will increase and it will be advantageous.
When a person is heterozygous for sickle cell anemia, it means it has one abnormal allele of the hemoglobin beta gene but doesn’t express the disease (like homozygous person).
On the other hand, a person heterozygotes for sickle-cell trait has a selective advantage in environments where malaria is present.
