Apparatuses, methods, and systems are disclosed for triggering HARQ-ACK feedback for a downlink slot set. One apparatus includes a receiver that receives a first control signal from a base unit for triggering HARQ-ACK feedback for a downlink slot set. The downlink slot set comprises multiple downlink slots. The apparatus includes a processor that identifies the downlink slot set in response to the first control signal and a transmitter that transmits UCI to the base unit in a slot determined by the first control signal. Here, the UCI comprises the HARQ-ACK feedback for the identified downlink slot set. The HARQ-ACK feedback for the downlink slot set corresponds to all downlink transmissions in the downlink slot set and is transmitted in one UCI.