IFNG and neoplasm: Recent studies, based on single cell RNA sequencing technologies and multicolor flow cytometry, resolved to accurately define “dysfunctional” (”exhausted”) tumor infiltrating PD-1+ T cells at different states of functional impairment, where “early dysfunctional” (or “progenitor exhausted”) cells expressed intermediate levels of PD-1 and showed maintained or even increased cytotoxic, IFNγ-producing and proliferative capacity32–35.