T-Mobile is facing a lawsuit filed by Washington State's Attorney General (AG) due to a cyber security incident that occurred in 2021. The telecom giant experienced a significant data breach last year, with the personal information of millions of customers being exposed. The AG's office has accused T-Mobile of failing to protect its customers' data adequately, leading to this legal action. This is the second legal challenge for the company regarding data breaches. In 2020, it agreed to a settlement following a similar data breach incident. Under that agreement, the company was required to implement several security measures to protect consumers' data better. The recent lawsuit suggests that T-Mobile has not complied with the terms of the 2020 settlement.