Chimpanzees can learn sign language to communicate with humans and can remember the name sign of individuals they have not seen for several years. They can also recognize themselves in mirrors and show signs of caring and mourning. They can even use symbols for objects and combine the symbols in a sequence to convey complex ideas.
They have complicated social groups where they form strong bonds and observe elaborate hierarchical structures. Researchers from Iowa State University and the University of Cambridge observed chimps in the wild making spears to hunt and using tools to crack open nuts and remove termites out of logs. They're capable of advanced problem-solving, including an experiment that proved they could outperform humans in a memory test.
In summary, chimpanzees are smart AF.