What is 'Pillar 1' deal, which US says India isn’t engaging with?

US claimed that India isn't engaging in negotiations regarding OECD's 'Pillar 1' tax deal. The deal focusses on multinational firms with at least €20-billion consolidated revenue and over 10% net profits. It'll mandate them to pay tax in locations where their customers/users are located, using a formula-based approach to allocate profit shares among different countries.