Both sides have verbally agreed to the 115-pound bout, though contracts have not yet been signed. UFC 239 is scheduled to take place at T-Mobile Arena and is headlined by a light heavyweight title fight between Jon Jones and Thiago Santos.
Gadelha (16-4) is a former two-time title challenger. She is coming off a loss to Nina Ansaroff at UFC 231 in December. The 30-year-old Brazilian lives in and trains out of Las Vegas.
Markos (9-6-1) has compiled a 5-5-1 record in the UFC since signing with the promotion in 2014. Originally from Iraq and now fighting out of Ontario, Canada, she recorded an impressive first-round submission over Angela Hill in her most recent performance in March.