A Study to Evaluate the Safety and Efficacy of Selinexor With or Without Pembrolizumab Versus Standard of Care in Previously Treated Metastatic Colorectal Cancer With RAS Mutations

Participants will receive selinexor oral tablets.

Participants will receive pembrolizumab intravenously.

Participants will receive trifluridine oral tablets as SOC.

Participants will receive tipiracil oral tablets as SOC.