When you send a transaction on a blockchain network, miners are responsible for processing and confirming it. However, miners often prioritize transactions with higher gas prices, which are fees paid by the sender.
As a result, transactions with lower gas prices can experience delays in processing. In a pool of numerous transactions, those with the lowest gas prices may not be picked up by miners, leading to them being stuck in a pending state.
In case your transaction wasn't processed with a low fee and is pending for more than 1 hour, the network may get less congested and the miners will pick up the transaction.
Eventually, if the transaction is not confirmed for a long time (depends on the blockchain's workload), it will be canceled and the cryptocurrency will be refunded.