The grid lines are moved backwards in z a bit so the normal plots are on top of them. You can move the heatmap back so it’s behind them. (Or move them forward)
f, ax, hm = heatmap(randn(100, 100), colormap = :Blues, colorrange = (-2, 8),
axis = (;
aspect = DataAspect(),
xgridcolor = :black,
ygridcolor = :black,
xgridwidth = 2,
ygridwidth = 2,
xminorgridcolor = :black,
yminorgridcolor = :black,
xminorgridvisible = true,
yminorgridvisible = true,
xminorticks = IntervalsBetween(5),
yminorticks = IntervalsBetween(5),
))
translate!(hm, 0, 0, -100)
f
