Mandril. The males get brilliantly colored faces during breeding time which is what you are likely familiar with seeing. Photographing Mandrill in the wild, even a semi-habituated group like this one, is difficult. They tend to be shy towards and stayed just behind enough branches and leafs so they felt safe and could keep an eye on us. The shots might help illustrate how they live in the wild. This group was over 600 members!
Lope National Park, Gabon July 2019 (below) and July 2022 (above)