ICD-10-CM > S00-T88 > T36-T50 > T45 > T45.A > T45.AX > T45.AX4 T45.AX4 Poisoning by immune checkpoint inhibitors and immunostimulant drugs, undetermined Non-Billable/Non-Specific Codes T45.AX4A..., initial encounterT45.AX4D..., subsequent encounterT45.AX4S..., sequela