PMEL and neoplasm: To create a gRNA library for in vivo screens of OC‐associated immune regulators, we first performed a genome‐wide immune screen to determine which candidates can modulate tumor sensitivity to in vitro T cell‐mediated killing, as previously described.[5] In the in vitro OC screen, we used a Cas9 and gp100‐expressing ID8 cell line (ID8/GC), which can be recognized by gp100‐specific T cells derived from Pmel mice (Figure S1A, Supporting Information).