Human-Robot Collaboration (HRC) has played a pivotal role in today's human-centric smart manufacturing sce-narios. Nevertheless, limited concerns have been given to HRC uncertainties. By integrating both human and artificial intelligence, this paper proposes a Collaborative Intelligence (CI)-based approach for handling three major types of HRC uncertainties (i.e., human, robot and task uncertainties). A fine-grained human digital twin modelling method is introduced to address human uncertainties with better robotic assistance. Meanwhile, a learning from demonstration approach is offered to handle robotic task uncertainties with human intelligence. Lastly, the feasibility of the proposed CI has been demonstrated in an illustrative HRC assembly task.