Both Uses of

deception
in
The Immortal Life of Henrietta Lacks

This was a time when "benevolent deception" was a common practice—doctors often withheld even the most fundamental information from their patients, sometimes not giving them any diagnosis at all.†
Chpt 1.8 *

deception = the act of lying to or misleading someone; or something that misleads

The deception was for his benefit—he was withholding information because patients might have refused to participate in his study if they'd known what he was injecting.†
Chpt 2.17