The Hyksos were a group of Asiatic and Semetic people who occupied Egypt during the 17th and 16th centuries BCE. An Egyptian leader by the name of Ah-mose (also known as Amosis) was the founder of the Eighteenth Dynasty in 1550 BCE. When he came to power he managed to expel the Hyksos from Egypt and thus liberated the entire Egypt. His men then chased the Hyksos through the Sinai desert and through Canaan. Finally he reasserted Egyptian rule over areas such as Canaan and Nubia to ensure that such an occupation by the Hykso would never happen again.
Some Christian apologetics try to claim that the Hyksos were in fact the Israelites, however this is highly improbable. The Hyksos introduced new weapons into Egypt such as the composite bow and the horse drawn chariot. The nation of Israel in the 17th century BCE did not have this type of military technology. It has been suggested by leading archaeologists that if the Israelites existed at all, they were nothing but a small nomadic group at this stage.
Finaly the Hyksos left Egypt in the 16th century BCE whilst the Israelites were supposed to have left Egypt in the 13th century BCE. Thus it's clear that the Israelites could not have been the Hyksos and that these were two distinct groups.