If you have more than one chatbot, for example for sales and for support, you do not want all of them to know everything. With knowledge teams you decide which knowledge is shared and which stays with one bot.
Every bot has its own private knowledge base. What you put there is used only by that bot. Put knowledge in a knowledge team and every bot in that team can use it: question-and-answer pairs, knowledge articles, documents and scanned pages.
A bot can be a member of several teams. A support bot can use the knowledge of the support team and of the product team, without you having to enter anything twice.
A bot can also hand a conversation over to a specialist bot in the same team. You state what a bot specialises in; the visitor sees a notice and can continue or cancel. A hand-over is only possible to a bot in the same team.
How many bots and knowledge teams you can create depends on your package. You manage teams in the portal; the help assistant Einstein Assist can help you with that.