This is a study to determine the recommended dose of MK-8628 for further studies in participants with acute myeloid leukemia (AML) including AML de novo and AML secondary to myelodysplastic syndrome (MDS) and in participants with diffuse large B cell lymphoma (DLBCL). The recommended dose will be established by evaluating dose limiting toxicity (DLT), safety, tolerability, and early efficacy signals.