The 205-pound contest will serve as the main event of a UFC Fight Night on March 12. The UFC has not yet announced a location for the event.
A former title challenger, Santos (22-9) is coming off a decision win over Johnny Walker in October. The Brazilian fighter challenged former champion Jon Jones for the title in July 2019 and suffered a serious knee injury in a decision loss. He dropped his next two bouts coming off knee surgery before rebounding in October.
Ankalaev (16-1) is one of the fastest-rising contenders in the division. The 29-year-old Russian is on a seven-fight win streak, including a decision over former title challenger Volkan Oezdemir at UFC 267 two weeks ago.