After the company rebranded itself to Lenovo, it merged with IBM's PC business which produced its ThinkPad line in 2005, after which it rapidly expanded abroad. In 2013, Lenovo became the world's largest personal computer vendor by unit sales for the first time, a position it still holds as of 2024.They basically bought IBM's good reputation name and style and used it for both IBM-alikes and budget machines.
Some of it was good machines, some of it was crap.
So Thinkpads are still designed in ex-IBM Lenovo Japan