Boba Fett was a Mandalorian bounty hunter. He was a clone of his "father", Jango Fett, who lived before the Galactic Civil War. Toward the end of the war, Boba was working "on retainer" for crimelord Jabba the Hutt, having gained Jabba's favor by bringing him the frozen body of Han Solo.
Boba Fett was "killed" when he fell into the mouth of the Sarlacc, but EU writers decided to have him escape that death. A cult of Boba Fett fanwhores sprouted as a result. Boba Fett's survival has since become a part of the Star Wars canon with his appearance in The Mandalorian series on Disney+.