A Clinical Study to Test if an Investigational Treatment Called BNT314 When Used in Combination With Another Investigational Treatment BNT327 and Chemotherapy, is Beneficial and Safe for Patients With Advanced Colorectal Cancer

Key Inclusion Criteria: * Have unresectable histologically confirmed adenocarcinoma of the colon or rectum. * Have confirmed non-microsatellite instability-high (non-MSI-H)/pMMR mCRC per Food and Drug Administration (FDA)/European Commission (EC) approved test or based on local testing. * Have measurable disease defined by RECIST v1.1. * Must provide a tumor tissue sample (formalin-fixed, paraffin-embedded or tissue slides) collected before C1D1 for enrollment. A newly obtained tumor sample is preferred. If it is not feasible to obtain a recent tumor sample, participants can provide archival tumor tissue (less than 2 years prior treatment). * Have Eastern Cooperative Oncology Group Performance Status of 0 or 1. * Have a life expectancy of ≥12 weeks. * Have an adequate organ and bone marrow function within ≤7 days of Day 1 as defined in the protocol. * Have had an adequate previous treatment washout period before randomization/enrollment as defined in the protocol. Inclusion criteria applicable to only protocol-specific cohorts: * Have received at least two previous lines of therapy for metastatic disease. * Have progressed following first-line chemotherapy as specified in the protocol. * Have not received prior systemic therapy for MSS/pMMR mCRC. Participants who received chemotherapy, radiotherapy, or chemoradiotherapy with curative intent for non-metastatic disease in the neoadjuvant or adjuvant setting are eligible for the study if therapy was completed at least 6 month…