I read an article explaining the cancelling of the show. Apparently, the show has lost over 50% of its revenue over the past 5 years and the show was losing over $40 million a year. Since Paramount bought CBS last year, Paramount has been getting rid of programs that were losing money, it's an easy business decision.
But of course, it's all Trump's fault. It has nothing to do with the show losing viewership and ad revenue for years.