Inclusion Criteria:

          -  Acute myeloid leukemia (AML) according to World Health Organisation (WHO) 2016
             criteria and fulfilling all of the following criteria that defines those who are "not
             candidates for intensive chemotherapy":

               1. greater than or equal to (>=)75 years of age or

               2. less than (<) 75 years of age with at least one of the following comorbidities:
                  Eastern Cooperative Oncology Group (ECOG) Performance Status of 2; Severe cardiac
                  comorbidity defined as congestive heart failure or ejection fraction less than or
                  equal to (<=) 50 percent (%); Severe pulmonary comorbidity defined as documented
                  pulmonary disease with lung diffusing capacity for carbon monoxide (DLCO) <=65%
                  of expected, or forced expiratory volume in 1 second (FEV1) <=65% of expected or
                  dyspnea at rest requiring oxygen; Moderate hepatic impairment defined according
                  to NCI organ dysfunction classification criteria (total bilirubin >=1.5 up to 3
                  times upper limit of normal [ULN]); Creatinine clearance <45 milliliter per
                  minute per 1.73 meter square (mL/ min/1.73 m^2); Comorbidity that, in the
                  Investigator's opinion, makes the participant unsuitable for intensive
                  chemotherapy and must be documented and approved by the Sponsor before
                  randomization

          -  De novo or secondary AML

          -  Previously untreated AML (except: emergency leukapheresis, hydroxyurea, and/or 1 dose
             of cytarabine [example: 1-2 gram per meter square {g/m^2}] during the Screening Phase
             to control hyperleukocytosis. These treatments must be discontinued >=24 hours prior
             to start of study drug). Empiric all trans retinoic acid (ATRA) treatment for presumed
             acute promyelocytic leukemia (APL) is permitted but APL must be ruled out and ATRA
             must be discontinued >=24 hours prior to the start of study drug

          -  Not eligible for an allogeneic hematopoietic stem cell transplantation

          -  ECOG Performance Status score of 0, 1 or 2

        Exclusion Criteria:

          -  Acute promyelocytic leukemia

          -  Leukemic involvement or clinical symptoms of leukemic involvement of the central
             nervous system

          -  Use of immune suppressive agents for the past 4 weeks before the first administration
             of cusatuzumab on Cycle 1 Day 3. For regular use of systemic corticosteroids,
             participants may only be included if free of systemic corticosteroids for a minimum of
             5 days before the first administration of cusatuzumab. Treatment of adrenal
             insufficiency with physiologic replacement doses of corticosteroids are allowed

          -  Prior treatment with a hypomethylating agent for treatment of AML or myelodysplastic
             syndrome (MDS)

          -  Active malignancies (that is, progressing or requiring treatment in the last 24
             months) other than the disease being treated under the study

          -  Any active systemic infection

          -  Known allergies, hypersensitivity, or intolerance to cusatuzumab or azacitidine or its
             excipients (that is, mannitol, an excipient of azacitidine)