State and Local IT Modernization and Cybersecurity Improvement Act This bill establishes in the Department of Homeland Security (DHS) grant programs to assist states and Indian tribal governments with emergency information technology (IT) expenses and modernization, and to assist state, local, tribal, or territorial governments to address cybersecurity risks and threats. Specifically, the bill establishes a Public Health Emergency Information Technology Grant Program to make grants to states and tribal governments for emergency IT expenses during a public health emergency, specifically COVID-19 (i.e., coronavirus disease 2019). The bill establishes in DHS the Modernizing IT Grant Program to make grants to states and Indian tribal governments to modernize IT to securely enable digital delivery of government services. The Cybersecurity and Infrastructure Security Agency (CISA) shall distribute grants to states for addressing cybersecurity risks and threats to the information systems of state, local, tribal, or territorial governments. The CISA must (1) establish a State and Local Cybersecurity Resiliency Committee; (2) develop and make publicly available a Homeland Security Strategy to Improve the Cybersecurity of State, Local, Tribal, and Territorial Governments; (3) conduct a study to assess the feasibility of implementing a short-term rotational program for the detail of approved government employees in cyber workforce positions to the agency; and (4) develop a resource guide for use by state, local, tribal, and territorial government officials.