CD8A and pachyonychia congenita: Despite the presence of neoantigens and activatable T cells in some patients, there is often a lack of response to immunotherapeutic approaches.[30,31] PC is characterized as a “cold tumor,” marked by a paucity of CD8+ T-cells within the tumor microenvironment, as observed in both human samples and mouse models.[4,5] Our MR study corroborates this observation, showing that out of 24 immune cell phenotypes with a causal link, 16 were positively associated with PC, suggesting an immune evasion profile characteristic of this malignancy.