Heterolysis of carbon-bromine bond produces

In heterolytic cleavage, bond cleavage takes place with an unequal splitting of electron pairs between the bonded atoms. Such types of cleavage forms a cation and an anion. 

The heterolysis of C-Br bond produces one cation and one anion. As C is less electronegative, so after cleavage it becomes a cation as it carries a positive charge. Whereas, Br is more electronegative atom than C, therefore it is an anion because of having a negative charge.