The present invention relates to a wireless communication system and, in particular, to a method and an apparatus therefor, the method comprising: receiving first downlink control information (DCI) including downlink scheduling information and information on a HARQ-ACK feedback type; transmitting a HARQ-ACK feedback regarding a first physical downlink shared channel (PDSCH) corresponding to the downlink scheduling information, on the basis of the HARQ-ACK feedback type indicating a first type; and delaying transmission of the HARQ-ACK feedback regarding the first PDSCH or transmitting a previously-received HARQ-ACK feedback regarding a second PDSCH, on the basis of the HARQ-ACK feedback type indicating a second type.