First, get the corresponding iterm colorscheme: https://github.com/mhartington/oceanic-next-iterm
Then in iTerm go to Preferences > Profiles > Colors
Change the background to 0b053d to match the screenshot
Add the following lines to your .vimrc:
Plugin 'poetic-labs/pastelesque'
colorscheme pastelesque
Then in Vim run
:PluginInstall