The immune escape phenotype is characterized by low levels of T cells and B cells, with a high infiltration of FOXP3+ regulatory T cells (Tregs), a higher tumor budding rate, and mutations in CDKN2A, SMAD4, and PIK3CA. Notably, this subtype displays significantly higher levels of CA19-9, which is typically associated with poor prognosis. The gene discussed is PIK3CA; the disease is neoplasm.