It’s not simple to transliterate Russian names to English. Sometimes there is a unique mapping, or at least a standard mapping, of a particular name, but often there is not.
An example that comes up frequently in mathematics is Pafnuty Lvovich Chebyshev (1821–1894). This Russian mathematician’s name Пафну́тий Льво́вич Чебышёв has been transliterated at Tchebichef, Tchebychev, Tchebycheff, Tschebyschev, Tschebyschef, Tschebyscheff, Čebyčev, Čebyšev, Chebysheff, Chebychov, Chebyshov, etc.
The American Mathematical Society has settled on “Chebyshev” as its standard, and this is now common in English mathematical writing. But things named after Chebyshev, such as Chebyshev polynomials, are often denoted with a T because the French prefer “Tchebyshev.”
There is an ISO standard, ISO 9, for transliterating Cyrillic characters into Latin characters. Under this standard, Чебышёв becomes Čebyšëv. This maps Cyrillic into Latin characters with diacritical marks but not into ASCII. The AMS realized that the vast majority of Americans would not type Čebyšëv into a search bar, for example, and chose Chebyshev instead.