PCI DSS, or Payment Card Industry Data Security Standard, is a set of security standards designed to ensure that all companies that accept, process, store, or transmit credit card information maintain a secure environment. It encompasses requirements for secure handling of cardholder data, network security, vulnerability management, access control, and regular monitoring and testing of security systems. Compliance with PCI DSS is mandatory for any organization that handles payment card information, aiming to protect cardholder data from theft and fraud. 

PCI DSS is crucial for safeguarding sensitive payment card information and preventing data breaches, which can result in financial losses, legal liabilities, and damage to reputation. Compliance with PCI DSS helps businesses build trust and credibility with customers by demonstrating a commitment to protecting their payment card data. Additionally, PCI DSS compliance reduces the risk of security incidents and helps organizations avoid costly fines and penalties associated with non-compliance.