A Study to Evaluate INCB186748 in Participants With Advanced or Metastatic Solid Tumors With KRAS G12D Mutation

Inclusion Criteria: * ≥18 years old. * Locally advanced or metastatic solid tumor with KRAS G12D mutation. * For Part 1 and Part 2 Combination Group 1: Disease progression on or after prior standard treatment, or intolerance to or ineligibility for standard treatment, or no standard available treatment to improve the disease outcome. * For Part 2 Combination Groups 2 and 3: No more than 1 prior standard treatment. * Cohort-specific requirements as follows: * Parts 1a and 1d: histologically or cytologically confirmed malignant solid tumor of any tissue origin. * Part 1b * Disease Group 1: diagnosis of PDAC and at least 1 but no more than 2 prior standard systemic regimens for pancreatic cancer. * Disease Group 2: diagnosis of CRC. * Part 1c: Confirmed diagnosis of PDAC or CRC. * Parts 2a and 2b * Combination Group 1 (INCB186748 in combination with cetuximab): * Diagnosis of PDAC or * Diagnosis of CRC and ∘ Prior treatment in the advanced setting with a fluoropyrimidine-based chemotherapy regimen containing either oxaliplatin or irinotecan and * In Part 2a: ≤ 3 prior standard regimens. * In Part 2b: ≤ 2 prior standard regimens. * Combination Group 2 (INCB186748 in combination with GEMNabP) and * Combination Group 3 (INCB186748 in combination with mFOLFIRINOX): * Diagnosis of PDAC. * ≤ 1 prior standard systemic regimen for pancreatic cancer. * Measurable disease according to RECIST v1.1. * ECOG performance status score of 0 or 1. Exclusion Criteria: * Prior treatment with any KRAS inhibitor. * Known additional invasive malignancy within 1 year of the first dose of study drug. * History of organ transplant, including allogeneic stem cell transplantation. * Significant, uncontrolled medical condition. * History or presence of an ECG abnormality. * Inadequate organ function. Other protocol-defined Inclusion/Exclusion Criteria may apply.