CBS has cast two white actors (Poppy Montgomery and David Giuntoli) as the leads of a sci-fi pilot “Mission Control." Both roles were originally written for people of color (a bilingual Latina actor and a black actor, respectively). CBS claims they originally offered the roles to actors of color and those actors turned down the roles so they revamped the show. This is obviously bullshit, says this OP.
Montgomery will be playing Julie Towne, who was originally written as biracial (white and Latina) and bilingual, frequently speaking Spanish in the pilot. Montgomery will no longer be speaking Spanish on the show. Giuntoli will be playing Malik Stevenson, a NASA commander explicitly written as African American in the script.
CBS and the scriptwriter had no comment, but it is noted there are Latino and Nigerian-born actors in supporting roles because that makes it all better.
In October 2016, CBS launched a Drama Diversity Casting Initiative to diversify their shows. However, the majority of their 2017 shows are starring white actors.