band or ribbon

using CairoMakie

x = LinRange(-10, 10, 200)
fig = Figure(size = (600, 400))
ax = Axis(fig[1, 1], xlabel = "x", ylabel = "y")
band!(x, sin.(x), sin.(x) .+ 1; color = (:blue, 0.2))
band!(x, cos.(x), 1 .+ cos.(x); color = (:red, 0.2))
fig