The actor believes that they will not start filming for a couple of years.
We are at least three or four years away from Black Panther 2 if we take into account that actor Martin Freeman has recently declared that the filming of this expected sequel will not start until 2021.
Recently, Freeman confirmed that he will be part of this sequel since no one has told him to be out of the MCU, but unfortunately, we will not see him, nor the rest of Wakanda's inhabitants, in a long time. At least not in a leading role.
Black Panther 2 was not part of the multiple announcements that Marvel made in the last Comic-Con in San Diego, where they put dates and faces on the new projects that will form the so-called Phase 4 of the MCU. Therefore, we may see T'Challa and his people in Phase 5.
Freeman also seems clear that Everett Ross was not one of those affected by Thanos' first genocide and in those five years he would simply have been out of the spotlight.