A turbine blade or vane (1) has a shell (2), including a first side wall (8) and a second side wall (9), which are connected together at a leading edge (10) and at a trailing edge (11), which extend longitudinally from a root (7) to a tip (6) and which are connected together between leading edge (10) and trailing edge (11) by a plurality of inner ribs (13). In the inner region (12) of the turbine blade/vane (1), the ribs (13) form at least one cooling gas path (15), which guides a cooling gas flow from the root (7) to the tip (6) and, in the process, is deflected a plurality of times in serpentine shape from the outside to the inside and from the inside to the outside. In order to increase the life of the turbine blade/vane (1), at least one bypass opening (18) and/or at least one outlet opening (19) are arranged in the region of at least one rib (13), which deflects the cooling gas flow from the outside to the inside, the bypass opening (18) penetrating the rib (13) at the shell (2) and the outlet opening (19) penetrating the shell (2).