A turbine airfoil for a gas turbine engine comprising: an outer wall delimiting an airfoil interior, the outer wall extending span-wise along a radial direction of a turbine engine and being formed of a pressure sidewall and a suction sidewall joined at a leading edge and at a trailing edge; a trailing edge coolant cavity located in the airfoil interior between the pressure sidewall and the suction sidewall, the trailing edge coolant cavity being positioned adjacent to and extending out to the trailing edge and in fluid communication with a plurality of coolant exit slots positioned along the trailing edge; and an internal arrangement comprising an array of discrete fins located on both the pressure sidewall and the suction sidewall of the airfoil, the discrete fins located aft of the trailing edge coolant cavity and along of the trailing edge, the array of discrete fins configured to extend out into the interior of the airfoil without reaching the opposite interior sidewall, the discrete fins extending out into the interior of the turbine airfoil alternating from the pressure sidewall and the suction sidewall, the array of discrete fins being arranged in radial rows and interspaced radially by axial coolant passages in the turbine airfoil and interspaced axially by radial coolant passages in the turbine airfoil, wherein the axial coolant passages are fluidically interconnected via the radial coolant passages, the discrete fins form a zigzagging cooling flow passage axially along a chord-wise direction for a cooling fluid (Cf) between the pressure sidewall and the suction sidewall, wherein the internal arrangement further comprising at least one row of discrete radially running pins along the trailing edge of the airfoil, wherein the pins connect the pressure sidewall and the suction sidewall of the turbine airfoil. an outer wall delimiting an airfoil interior, the outer wall extending span-wise along a radial direction of a turbine engine and being formed of a pressure sidewall and a suction sidewall joined at a leading edge and at a trailing edge; a trailing edge coolant cavity located in the airfoil interior between the pressure sidewall and the suction sidewall, the trailing edge coolant cavity being positioned adjacent to and extending out to the trailing edge and in fluid communication with a plurality of coolant exit slots positioned along the trailing edge; and an internal arrangement comprising an array of discrete fins located on both the pressure sidewall and the suction sidewall of the airfoil, the discrete fins located aft of the trailing edge coolant cavity and along of the trailing edge, the array of discrete fins configured to extend out into the interior of the airfoil without reaching the opposite interior sidewall, the discrete fins extending out into the interior of the turbine airfoil alternating from the pressure sidewall and the suction sidewall, the array of discrete fins being arranged in radial rows and interspaced radially by axial coolant passages in the turbine airfoil and interspaced axially by radial coolant passages in the turbine airfoil, wherein the axial coolant passages are fluidically interconnected via the radial coolant passages, the discrete fins form a zigzagging cooling flow passage axially along a chord-wise direction for a cooling fluid (Cf) between the pressure sidewall and the suction sidewall,