Sublimation ink is printed onto transfer paper, which is then pressed against the fabric at high heat. The dye becomes a gas, enters the polyester fibers and becomes part of them. Nothing sits on top, so the print has no hand at all, cannot crack or peel, and the fabric stays breathable.
The chemistry sets the limits. It only bonds to polyester or polymer-coated items, and the higher the polyester content, the more vivid the result; on cotton it washes out. The dyes are transparent and there is no white, so they need white or very light fabric. For full coverage, fabric panels are printed before the garment is sewn, which is how all-over print jerseys and hoodies are made; pressing finished garments leaves white gaps at creases and seams.
Later screen printing on sublimated polyester can pull dye into the new ink, a form of dye migration. Ask for the fabric content and whether the artwork is set up per size. See types of shirt printing.