Embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media of retransmission mechanism for configured grant uplink transmission. The method comprising transmitting, to a second device, a transport block while starting a configured grant retransmission timer for autonomous retransmission of the transport block; in response to receiving, from the second device, a feedback indicating unsuccessful reception of the transport block, adjusting expiry time of the configured grant retransmission timer without starting the autonomous retransmission of the transport block; determining whether scheduling information for retransmission of the transport block is received before the adjusted configured grant retransmission timer expires; and in response to determining that the scheduling information is received, retransmitting the transport block while stopping the configured grant retransmission timer. In this way, the retransmission in the Hybrid Automatic Repeat Request process could be performed according to the uplink grant scheduled by the network device and therefore the retransmission efficiency for configured grant uplink transmission in unlicensed spectrum can be improved.