The 27-year-old Chilean has excelled with the Brazilians since signing from Montevideo City Torque in 2022.
He has collected three Betway Premiership titles as well as the African Football League, Intercontinental Cup and Champions League title.
Allende's current contract expires at the end of the current season and when quizzed about the situation, the former Santa Cruz and Necaxa midfielder appeared uncertain as to what the future held.
Speaking after their 2-1 African-Asian-Pacific Cup win over Al-Ahli, the player said in the Citizen: "I don't know (about next season), but what I know is that I am so happy to be at the club.
"We are grateful to everyone as a team. We are enjoying this time. I am preparing for the next game and competition."
Sundowns' win over Al-Ahli sees them progress in the competition against an as yet unnamed opponent and a potential showdown with Paris Saint-Germain, if they win the Challenger Cup.
"We don't know yet which club we will play in the final," Allende noted.
"We know that there's an opportunity to play against PSG. We watch them on TV. Our dream is to get there. We'll need to fight and do what is required to achieve that dream as a collective going forward."
