According to Chinese law, overdue credit cards are illegal and may result in jail time. Regarding the situation where the debt is one year overdue and the debt is about 50,000 yuan and cannot be repaid, please note the following points:

1. The length of the sentence varies depending on individual circumstances: the length of jail time depends on many factors , including the amount owed, how long it is overdue, whether there is willingness to repay, etc. Therefore, the exact prison term cannot be pinpointed.

2. Case handling methods: Banks usually resolve overdue credit card issues through legal means. They may hand the case over to the police, who will investigate the case and the prosecutor's office to prosecute. Ultimately, the court will make a ruling based on the specific circumstances of the case.

3. Possible outcomes of the court’s decision: According to Chinese law, there are two possible outcomes for criminal liability for credit card debts. One is probation, which means the defendant is sentenced to a certain period of supervision and assessment, during which he must perform certain obligations; the other is to actually go to jail and serve his sentence in prison.

In summary, a credit card that is overdue for one year and owes about 50,000 yuan may lead to jail time. However, the specific prison term depends on individual circumstances and the outcome of the court decision. In order to avoid this situation from happening, it is recommended to communicate with the bank in time when encountering repayment difficulties and seek solutions, such as applying for a repayment extension or debt restructuring.

Extended information: Overdue credit card is a breach of contract and may violate the "crime of refusal to pay labor remuneration" or "crime of contract fraud" in the criminal law. According to Article 223 of the "Criminal Law of the People's Republic of China", whoever refuses to pay a relatively large amount of labor remuneration or fails to pay it overdue shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and shall also or solely be fined. The sentence for contract fraud is determined by factors such as the amount, means of conduct, and social impact.

Although the above answers are only a general description of the situation and cannot give an exact prison term, it is strongly recommended to consult with relevant legal institutions or professional lawyers as soon as possible to obtain specific legal advice and help.