Subject is between 18 years old and 75 years old, inclusive Must be at least 5 years old and enrolling on SJMB12 At least 5 years old at time of consent to remediation intervention >= 11 and < 25 years old at enrollment Adult (? 18 years old) Treatment-naive participants with AML who are >/=75 years old Patients ? 18 years old Man or woman >= 18 years old. Patients must be at least 18 years old. DONOR: < 6 months old and > 75 years old Subjects 1 and 2 (in cohort 1) will be >= 12 years’ old Patients 18 to 70 years old The patient is ?18 years old. The patient is at least 18 years old. Patients 0-49 years old will be enrolled in Arm A or C (high-intensity) Patient must be at least 18 years old at the time of consent. Patients must be at least 18 years old. Is aged ?20 years old in Japan or ?18 years old in other countries Initially only patients who are >= 16 years old will receive HA-1 TCR T cell infusions on the protocol; younger patients may be screened, enrolled in the protocol and monitored for relapse but will not be eligible for infusion until at least one patient >= 16 years old has been treated and discussed with the Food and Drug Administration (FDA) At least 18 years old at the time of informed consent Age greater than or equal to 16 years old; if patients 16-17 years old are enrolled in the trial, they will only be enrolled after 3 patients >= 18 years old have been treated, and the treatment has been shown to be safe Patients ?18 years and ?80 years old (The 3 first patients at Dose Level 1 will be < 65 years old. Enrollment of patients ? 65 years old must be approved by the DSMB after the completion of cohort 1). Patient is ? 18 years old at the time of informed consent. Patients enrolled onto the dose-finding phase of the study must have an identified donor and transplant strategy prior to initiation of the lymphodepletion regimen. Patients enrolled in the Expansion Phase of the Study: Relapsed/Refractory Cohort • Patients ?18 years old with relapsed or primary refractory acute myeloid leukemia. Patients Enrolled in the Dose-Escalation Phase of the Study •Patients ?18 years and ?75 years old (The 3 first patients at Dose Level 1 will be <65 years old. Enrollment of patients ? 65 years old must be approved by the DSMB after the completion of cohort 1) Newly Diagnosed Cohort • Patients with newly diagnosed, untreated Acute Myeloid Leukemia (as defined by World Health Organization (WHO) criteria,) who meet criteria for the European Leukemia Net (ELN) Adverse genetics prognostic group. Eligibility criteria for UCART123 administration Creatinine =< 1.5 mg/dL for patients 12 years old and older and =< 1 for patients younger than 12 years old. Female ? 18 years old. IMMUNE RECONSTITUTION STUDY ONLY: Between 8 and 60 years old DONOR: Must be >= 14 years old > 18 years old Patients must be ? 18 years old. At least 18 years old; Man or woman >= 18 years old. DONOR: Less than 18 years old Male or female patients from 6 months to ? 21 years old at the time of study enrollment Patients ?18 year old Patients must be > 18 years old. Donor: Donor < 6 months old, > 75 years old The patient is ? 18 years old. The patient is ? 18 years old. Participants who are 16 to 17 years old would be enrolled after consultation with the Medical Monitor Are a male or female patient ?18 years old. DONOR: Children < 12 years old Adult Women (? 18 years old). Be 18 years old at the time the informed consent is signed ?18 years old. Patient must be ? 18 years old. Patients must be at least 18 years old. Men and women ?18 years old. Are a male or female participants ?18 years old. Patients ? 16 years old Patient must be at least 18 years old. Male or female patients ?18 years old. Patients 18 years old or greater Patients > or = 18 years old ? 18 years old at the time of informed consent. Patients must be >/= 18 years old. ?18 years old ?18 years old Male or female ?18 years old Donor >= 18 years old Male or female patient is ? 18 years old, Male and female TAM patients ? 2 years old at the time of first dose administration. Patients < 12 years old can only be included in the study after first IA has shown that it is safe and well tolerated in patients ? 12 years old (Section 3.5). Male or female patients ? 18 years old Is >18 years old; Male or female ?18 years old. Patient is an adult, female ? 18 years old at the time of informed consent ? 18 years old Men or women > 18 years old ?18 years old, diagnosed with persistent or chronic ITP Man or woman >= 18 years old. Subjects >=18 years old. ? 18 years old Part 2, dose expansion: Is the subject between 18 years old and 80 years old inclusive? The subject is at least 18 years old. Patient is an adult ? 18 years old at the time of informed consent. 18-39 years old Men or women > 18 years old The patient is ?18 years old. ?18 years old In patients > 60 years old, documented LVEF of less than or equal to 45% Patients must be greater than or equal to 18 years old. Men or women ?18 years old Male or female patients ?18 years old. Men or women ? 18 years old For patients < 60 years old: at least two induction chemotherapy treatments. For patients >= 60 years old: at least one induction chemotherapy treatment or alternative treatment. Females at least 18 years old; Male or female patients >= 18 years old Patients treated at collaborating sites and current St. Jude patients who are on therapy or within 3 years of completion of therapy must be =< 24 years old; all other St. Jude patients must be =< 21 years old Subject is female and is at least 18 years old DCG: Is an adult family member (at least 18 years old) of a patient with an advanced-stage cancer < 19 years old < 19 years old CAREGIVERS ONLY: Must be an adult (>=18 years old) Are at least 18 years old Are 8-17 years old Patients who are in close social contact with children under 5 years old Adult (?18 years old) 18-35 years old Male 18 to 60 years old Female 18 to 50 years old 18-40 years old, The patient is ?21 years old, >18 years old. FLT PET: will only be performed in patients >= 10 years old Research biopsies in consenting patients with MPNST: will only be performed in patients >= 18 years old Patient is < 18 years old at the time of the drug administration ?18 years old M/F at least 18 years old History of treatment for cancer or related illness diagnosed at =< 25 years old The patient is at least 18 years old. Women ? 18 years old