Since Reuters is writing this up like it's just the norm for Pakistani PMs to be charged with crimes, rather than giving context, here's an article explaining that the US pushed Pakistani lawmakers to remove Khan. He was friendly to Russia and visited Putin just at the moment that the Special Military Operation began (aka invasion of Ukraine). He was also on a serious anti corruption campaign which would have threatened the very strings the US pulled to unseat him. He is hugely popular in Pakistan, and when there was an attempted assassination the crowd rallied around him to protect him.
https://theintercept.com/2023/08/09/imran-khan-pakistan-cypher-ukraine-russia/