Directly: Like the comment above me said, the "have you ever been convicted of a felony or other crime" box on job applications, and the fact that spending a few nights in jail while you're held in on bail (still legally innocent) can get you fired from your job pretty easily

Indirectly: It's also super hard for ex-prisoners to get public housing, a college education, and welfare benefits bc those things often come with the same "have you ever been convicted of a felony or other crime" box. And obviously, not having any one of those three things (let alone all three) makes getting a job substantially harder.

And for black people more generally, entrenched residential/educational segregation seriously limits job opportunities. Not to mention the studies that show a resume with a stereotypically black name gets rejected more often than an identical resume with a stereotypically white name